FYI for those people with overheating issues with their VX

[rocket man]

Hi Everyone!!

I am an original owner of my VX with 235,000 miles on the clock and just now working on the 3rd radiator. Also, I know a little bit about auto repairs as I owned an auto transmission repair shop for many years. There has to be a difference between an OEM radiator and the typical aftermarket radiator.

The OEM original I had failed on me about 4 years ago, the plastic crown cracked. We just bought an aftermarket over the counter. I didn’t pay much attention to the old core just threw it away.

But there has to be a big difference. I never noticed, with the OEM radiator, this slow creeping up of the heat gauge in hot weather and on a steep grades. I even pulled a 16 foot Komfort Lite trailer 1000’s of miles mostly between Montana and Los Angeles. Never ever a heating probem with the OEM.

I was immediately dissatisfied with the after-market radiator. Yet, most (95%) of the time it was okay but the heat gauge seemed to wander alot more, whereas the OEM seemed to nail the needle just below midway point on the gauge consistently no matter the weather or load. So I started poking around on the internet and found a “two row” after market radiator on Ebay from a local distributor here in LA. I ordered it ($100 seemed pretty cheap to me) and 1 day later it was delivered. First of all, it was NOT 2 rows, second of all it was a exact duplicate of the aftermarket one I had in there already! Never paid much attention to it in the first time install, however this time we scoped it out closely. It’s a skinnyass radiator. I called the distributor and he said, “2 rows” was a typo and this was the only radiator available. I said, okay and I sent it back and they refunded my money, no problem. I didn’t need it because the “one row” radiator I already had in there was working ok. So I began to wonder if some of the VX owners with this gradual overheating on grades, etc. had an OEM radiator or the inferior type aftermarket version?:confused:

Now, fast forward to last week.. Boom! Cracked plastic crown in an almost identical place that happened to the OEM unit 4 years earlier. This is a regular drive so I needed the car pronto. I ordered a new one from another Ebay distributor. It came 2 days later. The box said, “American Eagle Radiator Company”… but my suspicion is it should say, “Chinese Buzzard Radiator Company”… :mad: It is an exact copy of the one we took out. Not just a little bit close but is exactly the same. BTW this is a very simple install even without a hoist. 10mm socket, 1 blade 1 Phillips head screw drivers, 2 feet of 3/8in power steering hose, 8 hose clamps( I use 8 cause I’m paranoid 4 will work) , one gallon undiluted anti-freeze + wawa. 1 hour or less install. I replaced the trans cooler line hoses too.

So far it works fine, but I don’t trust it. I know that a few VX owners have installed Ron Davis radiators and if possible maybe could kindly chime in here and report on how their all aluminum radiator works in this hot weather? I’d Like to learn more about it and how I would go about getting an exact copy of the radiator like, I think, VX Kat has. As I recall they are around $650.

Thanx
John

[VX KAT]

.
I find it really interesting SO MANY of us are now having O/H problems....maybe it's just time for certain age parts to die...:_thinking


My recent experience with new RD radiator in heat in Moab:
http://www.vehicross.info/showpost.php?p=258196&postcount=16


On trip to Vegas last week for the photo shoot, my temp gauge was all over the place:mado:...so frustrating....:_brickwal Air temp consistently 95-100.
Consistently going 65-75mph...so plenty of air flow!
Temp climbed going up big hills with A/C on.
Temp went down some with A/C off, but took quite a while to return to normal, even when going DOWNhill.
Sometimes I had to turn heater on...that was pleasant...:goof:, but it lowered it.
Fluid was low, added 1/3 gallon 50/50 on return trip. - Seemed to reduce frequency, but not always.
When slow or not moving, temp went way up. Going super slow around a block in Vegas with those crazy mobs, it skyrocketed and I pulled off into a hotel drive. :_brickwal
Twice it pegged on the white bar on H.
Twice pulled off to shut her down for a little while. Helped very little, would start to rise within minutes.

It clearly acted INCONSISTENT...would rise when just going on flat straight-away at 70-75.
Made it home OK, talked with mechanic next day.
Doesn't think it's thermostat since that's most likely to be a CONSISTENT problem...when mechanical thermostat goes, it's gone...wouldn't expect inconsistencies.
Spun fan with engine cold, seems somewhat restricted, but I'm not sure.
Decided to replace fan clutch.
Merlin advised there's been a redesign and you now HAVE to buy the new style fan clutch (~$250....OUCH :eek:) AND a new fan blade (~$100....OUCH again):eek:...
Arrived today, will get installed next week.
Fingers crossed....:_brickwal
Even with all this, I have NO regrets getting custom build...it's way cool, and it will give me more opportunity to have A/C on in hot weather (which is uber important to me...it's an MS thang)....we just gotta figger out what's not workin' right!
Repeat warning Bill gave me: NEVER use any coolant additives such as Purple Ice in this radiator..will eventually erode and leak.



Detailed specs on my Ron Davis radiator-
Has more cooling capacity than OEM
No plastic parts, all aluminum
RD Part number 1-24RO9397
Can call Bill Williamson at RD and order it with that number. He's SUPER helpful and explains everything in great detail.
About $600.

Bill Williamson
Ron Davis Racing Products, Inc.
7334 North 108th Avenue
Glendale, AZ. 85307
Tel- 623-877-5000 Ext.16
Fax- 623-877-5001
http://www.vehicross.info/showpost.php?p=244972&postcount=5



MORE specs on my RD radiator:
http://www.vehicross.info/showpost.php?p=245552&postcount=25



Thread on aluminum radiator build:
http://www.vehicross.info/showthread.php?t=20866&highlight=ron+davis

[vt_maverick]

There has to be a difference between an OEM radiator and the typical aftermarket radiator.

I think the main difference is that one is designed to outlast the manufacturer's warranty period (4 year 50K miles I think?) while the other is designed to last for the typical aftermarket warranty period, which is generally much less. It's simple business sense, aftermarket manufacturers have to sell for way less than OEM or nobody would buy them, so naturally they have to cut corners during manufacturing and can't offer the longer warranties.

Not that dealerships don't mark their parts way up anyway, I'm just saying that the system is perfectly designed to achieve the results you're seeing.

[blacksambo]

The more I read the more I respect Isuzu OEM parts.

[Etfren]

Just like Sue, my VX was overheating on the Top of the World trail in Moab this year, and has done the same on hot days climbing long hills here at home too, so I've been trying to come up with a solution for this too. I've got 2 10 inch electric fans in my rig but they don't seem to be any better (or worse) than factory, besides not having to worry about my fan clutch exploding again.

An idea my dad brought up and something I have been thinking about recently is mounting a sprayer system to mist the radiator with water to help cool it a little extra. I believe the STi (Wormgod want to chime in?) has a factory setup for this to spray cool water on the TMIC to help with heatsoak issues.

At least one of the top drift racers in Forumla D has a setup like this on his car to keep from overheating between runs because they spend a lot of time just sitting on the grid waiting. Other teams just carry a sprayer like you would use for weed killer and spray it down that way between runs.

[VX KAT]

Just like Sue, my VX was overheating on the Top of the World trail in Moab this year, and has done the same on hot days climbing long hills here at home too, so I've been trying to come up with a solution for this too. I've got 2 10 inch electric fans in my rig but they don't seem to be any better (or worse) than factory, besides not having to worry about my fan clutch exploding again..


Eric I didn't recall yours was doing it too...I remember MeowMix's was, and saw her hood up during our lunch break. Fan clutch exploding?...I musta missed that story!
I still can't believe so many VXs are now having this problem....all at the same time...:_thinking?

[rocket man]

Wow that is a bewildering dilemma you have VX Kat. That is a crazy maker. :mady:

I have a 89 Isuzu Amigo that I have also have had since new. Now in that one I had a two row (like yurs) Modine radiator put in years ago to cool down the little 4 cyl engine that just couldn’t handle pulling that trailer. After the install I could pull a bus up Pike’s Peak and it wouldn’t push the needle past the middle of the gauge.

That radiator of yours is the, “bomb” and should way way way over cool your engine. IMHO. But since it doesn’t….. from the description you describe I would take a real hard look at your thermostat. At 60-75 mph you should be getting plenty air through the radiator so that you really don’t need any fan at all. Personally I don’t think if you R&R the fan clutch and fan it will make any difference. Seems to me that your “inconsistent” engine temp variations are consistent with a thermostat that won’t fully open and restricting your coolant flow.. Another thing to me that points to a stuck thermostat is that you basically have same issue that you had with this new radiator that you had with old one… yet it has to be 25-50% more efficient. Yet you mentioned you noticed a little drop in the engine temperature when the heater was turned on… and that was only running through a teeny heater core with fan on. That water is running right out of the block through the heater core to make a noticeable difference in your temp gauge. If the “stat” is half closed or a quarter closed it amounts to a significant restriction that even a big "Mondo" radiator like you have can’t overcome. JMHO

It was 97 degrees in Santa Clarita today and I was chugging up down hills and it was nailed at just below midway on the gauge with the A/C on. And that’s with an “el cheapo” very thin non-oem cooler that I have no faith in for the long haul. I know from 1st hand experience it’s a pain the @#$ to change this part but I’d take a hard look it anyway. If you do end up swapping out the thermo be sure to order the little seals and “o” rings from Merlin once you get the plenum chamber off.

Good luck Kat

Oh yes and BTW thanks for all your links on your radiator... :bgwo::bgwo::bgwo: Im gonna get me one of those...:yesy:
Thanx
John

[JHarris1385]

Out of everyone overheating are most of you watching the gauge on the dash or does anyone have a Scangauge and have actual temp numbers?

Mine does not reach past the half way mark till somewhere around the 210s+

[Skydoo]

If everything temperature related has been ruled out, it is time to check the circulating aspect of the system; pump is not as efficient as before, worn out belt or gear, internal blockage etc..

[Etfren]

Eric I didn't recall yours was doing it too...I remember MeowMix's was, and saw her hood up during our lunch break. Fan clutch exploding?...I musta missed that story!
I still can't believe so many VXs are now having this problem....all at the same time...:_thinking?

Yup, it was pushing to the top of the gauge, and Mark's VX wasn't too far behind me in overheating either. He had a Scanguage, but I forget what temp's he said he was getting up to.

Yeah, my fan clutch was going bad (didn't look into why it was so loud until after it went) and must have locked up or something because it broke the mount for the fan in half and shredded most of the belt when it went. Didn't feel like messing with replacing all that stuff, so I had my mechanic swap in the electric fans.

[VX KAT]

Wow, thanks for all that detail rocketman. Mechanic also suggested new OEM thermostat, so that goes in next week too.
JH..I don't have a scan gauge, so relying on dash gauge....it has crossed my mind the gauge could be malfunctioning. I recall someone mentioning that possibility in an older thread, think it was Mark (MSHardeman).

Since so many have recently had the fan clutch die, I decided to replace, even though it's lower on the possibility list.
I can't really hear the fan, and read two owners said they could really hear a difference after replaced.....and I liked the idea of getting the newer design. Figure it's likely better, not worse.

Mechanic will be checking for other possibilities as well next week.

Interesting to see all 4 out 5 of us on Top Of The World had the same problem, (anybody know if Jon had problems too?)
It wasn't THAT hot..maybe 92-93....but the trail sure was much rougher, and therefore, slower than 2 years ago.

[rowhard]

I too was having overheating issues, had been noticing prior to rad, water pump, timing belt change along with some other stuff. this that the temp gauge seemed high normal. Hooked up the scan gage after parts change sure enough, was as high as 218 under normal driving during the one week of hot weather here. Was dreading the thermostat change then read the tread about the fan clutch. More money, (150.00 new) but could be a easy fix. Sure enough, temps running no higher then 184 and normally in the 170's since change. So, moral of the story, do the check on your fan clutch to see if that might be the cause.

[VX KAT]

Got the new fan clutch, fan blade and thermostat installed.
Merlin advised a redesigned OEM fan clutch is the only one available now, and requires a new fan blade as well. New fan clutch is now $250 and blade $100...:eek: OUCH! Old fc was around $70 IIRC....:(

Interesting, new fan has 9 blades, old has 11. Blade shape and curve are also very different. I didn't measure either of them, but visually, it looks like there may be more surface space on the new blade, but not sure.

Like a few others said, I think I can hear more roar from the fan when the A/C is on, compared to before....but not a huge amount.

I thought for sure the new blade wouldn't fit in the old shroud, but it did, mechanic said it was tight. And Dub's tread plate cover could stay as well. :thumbup:
If this solves my O/H problems, I guess I'll never know if it was the new clutch or JUST the new blade....hmmmm :_thinking

Let's hope the redesign means more air! :thumbup:

Going to make a Phoenix run in a few days when it's supposed to be 102. Going to try to really tax it on one steep section of I17 where the elevation rises about 2000 ft in about 2-3 miles, with full A/C going and see what happens. There's warning signs to turn off A/C, and big rigs and regular cars often overheat and are pulled off to the side.

I'm curious, anybody know why the blade arrangement on both have one space between blades that's larger than all the others?

http://www.vehicross.info/gallery/data/500/DSCN5262.JPG

http://www.vehicross.info/gallery/data/500/DSCN5263.JPG

http://www.vehicross.info/gallery/data/500/DSCN5728.JPG

[evillecutter]

looks like it would push much more air

[Scott Larson]

[QUOTE=VX KAT;265369]Got the new fan clutch, fan blade and thermostat installed.

I'm curious, anybody know why the blade arrangement on both have one space between blades that's larger than all the others?


I'm guessing it has something to do with accoustics, making it quieter...:_confused

[evillecutter]

wondering about that odd blade gap too...

[samneil2000]

Maybe it's for room for an arm or wrench or something if you're workin on something around there???

[rocket man]

Hi VX Kat! :bwgy: I think it has something to do with damping the fan/propeller noise. Albeit, not that well:frowny:

The new fan you put in looks very similar to the vertical stabilizer fan on the super, not so secret, Stealth Copter that crashed on the Bin Laden raid. Their fan blades were designed around super quiet operation.

Every VX owner seems to notice the fan noise, guess I got used to it. Now because of this thread I'm noticing it again :mady:

Good luck John,

BTW still holding off on that Davis Radiator... Im gonna do it but my Chinese cheapo seems to be better than the old cheapo I took off. Anyway bought a Samarai last week and thats using up a litttle of my time and money. Keep us posted and let us know if that new fan works!!:grino:

[IndianaVX]

well, add me to the list. although i know kinda whats causing my overheating. Dubs favorite O ring under the intake, and thermostat while im in there. but while looking things over, i got to looking at my fan blade.....hmmm

sooo, here is my question. I will type slowly... In Kats picture above, of the origonal fan blade, would the side that is facing up be the side that is attached to the fan clutch, in other words, would that side be facing the engine? because thats the way mine is. the cups of the fan are facing the front, facing the radiator. with the rotation of the engine being what it is, the fan is slicing thru the air, instead of cupping and blowing the air.

its been like this for over a year, with absolutly no cooling issues, but, did i somehow put my fan on backwards?

[Scott Larson]

With the engine running, the fan better be pushing air towards the engine, otherwise you've got it on backwards. If so, I'm surprised you got away with it for even a day!

[89Vette]

That new, curved blade fan should be quieter too. Curved fans (like the SPAL type) are definitely the most quiet going. I'm going to convert my vette to a 3600 cfm SPAL-shaped unit.

On the VX, changing to an electric fan might make more sense. I saw on the vette forum, this (http://www.haywireinc.com/index.cfm/page/ptype=product/product_id=51/category_id=27/home_id=3/mode=prod/prd51.htm) variable temp control that looks promising.

OTOH, I know there's a thread on electric conversions (here) that I haven't looked at yet. But, I'm not having cooling issues at this point. Only wondered about a quieter fan someday....

[VX KAT]

well, add me to the list. although i know kinda whats causing my overheating. Dubs favorite O ring under the intake, and thermostat while im in there. but while looking things over, i got to looking at my fan blade.....hmmm

sooo, here is my question. I will type slowly... In Kats picture above, of the origonal fan blade, would the side that is facing up be the side that is attached to the fan clutch, in other words, would that side be facing the engine? because thats the way mine is. the cups of the fan are facing the front, facing the radiator. with the rotation of the engine being what it is, the fan is slicing thru the air, instead of cupping and blowing the air.

its been like this for over a year, with absolutly no cooling issues, but, did i somehow put my fan on backwards?

Dave-
I matched up the blade with my pic, the blades are cupped down, away from the camera. (Despite the blade at the 9 o'clock position appears to be cupped up, it's not).
http://www.vehicross.info/gallery/data/500/DSCN5728.JPG




I then matched it up to this pic from before I had my new radiator installed...It's definitely cupped toward the engine so theoretically, this is the factory position.
So if yours is now cupped toward the front, I believe it's backwards.
http://www.vehicross.info/gallery/data/500/DSC_0292.JPG




This is other side, cupped toward camera, which is facing the engine.
http://www.vehicross.info/gallery/data/500/DSCN5731.JPG

[blacksambo]

Great info! Thx

[VX KAT]

First off....I don't know much about the cooling system, so some of my questions may be very elementary....:o

Taking VX on a trial run tomorrow to test for overheating. Going to be 103 air temp in Phoenix, and A/C will be running coldest setting and fan at highest speed.
It's about 200 miles round trip. About 3 hrs of it will be city driving around town doing errands.




Today noticed I could hear kind of a whining/humming from the engine when A/C was on, and I had driver window down.
It stopped when I turned A/C off.
Heard it mostly when slowing for a light. It slowed as truck slowed.
but never stopped completely...I assume this is the fan?
I also hear a clicking sound and then a hum when I turn A/C ON... I assume that's the A/C compressor kicking on/off?



Does the A/C control the fan clutch when it needs it? Since the fan obviously runs w/o A/C, I'm wondering if the A/C can cause it to speed up when it recognizes the need. Or is the fan just responding to the engine temp it's reading, regardless if it's the A/C causing the strain or any other factor?



If the A/C fan speed is lower, is that a lower load on the fan clutch?



I believe I should keep the A/C temp at the coldest setting, to keep the compressor working at as max as I can get it, correct?



If I drive in D3 to keep the revs higher, trying to tax the engine even more, will that dramatically skew my test? Or can I go in D3 for a while, then go back to normal D4?



I don't really want to turn off the engine to allow any cooling whatsoever, but, based on my Las Vegas trip last month, it really didn't cool off much, even after an hour. Is it negligible?



There's a short stretch of Interstate 17 that raises over 2000 ft in elevation in just a few miles. Common area for cars and rigs to overheat. Will I tax the engine a bit more if I go up this steep section slower, which means less air flow into radiator?
The right lane is often moving at only about 30 mph because of many big rigs.
This steep stretch is on the return trip, so maybe it will reveal something.



Any other TIPS OR SUGGESTIONS/DO's/DON'Ts to test for overheating?



p.s....Hubby is on stand by to come get me while roadside assistance is on the way, if necessary. :thumbup:

[tom4bren]

First off....I don't know much about the cooling system, so some of my questions may be very elementary....:o

Taking VX on a trial run tomorrow to test for overheating. Going to be 103 air temp in Phoenix, and A/C will be running coldest setting and fan at highest speed.
It's about 200 miles round trip. About 3 hrs of it will be city driving around town doing errands.




Today noticed I could hear kind of a whining/humming from the engine when A/C was on, and I had driver window down.
It stopped when I turned A/C off.
Heard it mostly when slowing for a light. It slowed as truck slowed.
but never stopped completely...I assume this is the fan?
I also hear a clicking sound and then a hum when I turn A/C ON... I assume that's the A/C compressor kicking on/off?

Bingo. Hopefully the humming is coming from the new clutch & will go away as it breaks in. Do take the time though to check to see if anything is rubbing. Double chech the shroud for any signs of contact with the fan blades (they change shape slightly as the fan is spinning & may contact while in motion but not at static).


Does the A/C control the fan clutch when it needs it? Since the fan obviously runs w/o A/C, I'm wondering if the A/C can cause it to speed up when it recognizes the need. Or is the fan just responding to the engine temp it's reading, regardless if it's the A/C causing the strain or any other factor?

The fan should run all the time while the AC is on. The engine turns it on & off as needed with temperature. The fan is not adjusted for speed by the AC (it's either on or off). The fan speed will change with the engine speed though. In reality, the fan speed isn't being adjusted to run faster with the engine speed to pull more air - it's simply a matter of the fan being driven by the engine and spins at the respective speed.


If the A/C fan speed is lower, is that a lower load on the fan clutch?

No. AC is on or off just like in your house. It turns on to get the cabin temp down to a few degrees below what you set it for & then turns off. When the cabin temp rises a few degrees above the set temperature, the AC turns back on & the cycle starts all over. The cabin fan just circulates the air.


I believe I should keep the A/C temp at the coldest setting, to keep the compressor working at as max as I can get it, correct?

Yes but only around town. It sounds like your overheating issues are associated with the slow crawl rather than highway speeds.


If I drive in D3 to keep the revs higher, trying to tax the engine even more, will that dramatically skew my test? Or can I go in D3 for a while, then go back to normal D4?

With the engine running at higher RPMs, you would certainly be putting more stress on the cooling system. Just don't over rev your engine for long periods of time (remember that you've already experienced oil consumption at highway speeds that you don't on 'round town driving). Hate to see you blow your engine trying to test your cooling system.


I don't really want to turn off the engine to allow any cooling whatsoever, but, based on my Las Vegas trip last month, it really didn't cool off much, even after an hour. Is it negligible?

Turning off the engine is certainly the best bet if you're starting to run hot so that the engine will stop trying to dump more heat into the already hot system. It is however a 300 lb block of metal sitting inside a fairly closed chamber. It'll take a while for that heat to dissipate. Open the hood & it'll cool much faster.


There's a short stretch of Interstate 17 that raises over 2000 ft in elevation in just a few miles. Common area for cars and rigs to overheat. Will I tax the engine a bit more if I go up this steep section slower, which means less air flow into radiator?
The right lane is often moving at only about 30 mph because of many big rigs.
This steep stretch is on the return trip, so maybe it will reveal something.

I don't think you'll see much difference between going 30 mph & going 60 mph up that hill. When your cooling system is operating correctly, I'm guessing that the fan almost never turns on above 20 mph. The radiator fan on my Eclipse doesn't come on automatically anymore (I know ... I know ... I should fix that - I will when I get tired of procrastinating). As long as I'm moving at speeds above 15-20 mph, I don't have to worry about it. Unfortunately with my commute there is a lot of sitting in traffic so I just hit the AC or Defrost till the temp comes back down (fans still come on when compressor is on).


Any other TIPS OR SUGGESTIONS/DO's/DON'Ts to test for overheating?



Pray:)

p.s....Hubby is on stand by to come get me while roadside assistance is on the way, if necessary. :thumbup:

See if your mechanic has a scanguage or a temp guage that you can borrow for your test. If I wasn't using my scanguage this weekend, I'd send it to you. Sorry!

EDIT: Of course everything I've said is completely inaccurate if it's your thermostat that's causing the problem.

[VX KAT]

See if your mechanic has a scanguage or a temp guage that you can borrow for your test. If I wasn't using my scanguage this weekend, I'd send it to you. Sorry!

EDIT: Of course everything I've said is completely inaccurate if it's your thermostat that's causing the problem.

THANKS Tom!
We replaced the thermostat at same time new fan clutch etc...OEM of course.
Ironically, I just bought a SG2, but it hasn't arrived yet. I decided I want to know the engine temp/coolant temp, and we want to know how the tranny is handling towing on our other truck. (It claims to come with a tranny cooler, standard). Oh heck, who am I foolin', I just wanted one to play with and learn all kinds of new useless info! :laugho:
I'm running out of 100+ degree days, so I decided to try it now anyway.

[tom4bren]

I'm running out of 100+ degree days, so I decided to try it now anyway.

Boiling down the many words to few:

Drive it like you always drive it. It sounds like your trip will be challenging enough without trying to put extra strain on the cooling system.

Best o' luck & let us know how it turns out.

[frankd14321]

I started having overheating issues this summer. I live in the desert at 4,000 ft elevation and it gets to 120 degrees here sometimes.. So i expect some overheating in most cars.. But this was quite often. So I drained, flushed the radiator... put 20% anti freeze and the rest distilled water and redline water wetter. Now my overheating problem is gone. I'm still going to look into new fans though, after 12 years I doubt the OEM fans are spinning at the same RPMS.

For those of you who are against running mostly water, this is the same setup I use in my 400+ hp ls1 Camaro and my 500+ HP 2Liter Turbo Evo boosting 35psi. Also my cars are all garaged and the weather never gets much below freezing here.. And I typically change the radiator fluid in the winter to about 40% anti freeze.

I also realize many of you live in colder places and cannot run this setup, and some of you may be doing this already and still having issues... But i'm just sharing.

[IndianaVX]

Well, replaced the thermostat today, flipped my fan over to the correct side (again, never had an overheating problem since it was off last dec when I replaced head gaskets.

So, the original topic being bad radiators, but bad because of cracks. Should I suspect the radiator, even if there are no cracks? What is the process of deciding wether a radiator is good or bad? Just elimination?

The truck today, on start up after thermostat replacement, I had the heat on high while I filled the raidiator, the gauge read halfway, but I had no heat. So I drove it around the block a couple of times, gauge still pointing down halfway (normal position) then all of the sudden, I had FULL BLASTING HEAT! so drove a bit further, and the gauge started creeping up to the hot mark turned around to drive back to the house, ( this whole time I have heat on high) and the gauge starts to creep back down and staying at the normal position. So I continue driving a bit more, but I turn the heat off, and temp gauge starts to climb again, turn heat on high, gauge goes down to normal.

Does any of this sound like a reason to suspect the radiator?

[VX KAT]

My test run today was kind of inconclusive....:_thinking


Normal with full A/C all the way down, 80 miles at 70-75mph, air temp 104, full sun, in Phoenix.:eek:
City driving, stop/go, for about 20 minutes ->normal
Turned off while in restaurant 45 mins
Sat in car 5 mins, full A/C full, waiting for steering wheel to cool down --> Normal
Minutes later, driving around shopping center slowly --> Started to go up, between 70-75% of dial.
Continued slower city driving a few miles, --> Stayed around 70%-75%
Stopped for 25 mins, engine off
Started up and was at 65%
Freeway at 65mph for a few miles --> Normal
Stopped for 30 mins, engine off
Started up and was at 65%
Highway for 80 miles, 65mph --> Normal within a few mins
Climbing the steep elevation part of route--> Normal for 2/3 of 4 miles
Went up to 65%
Returned to normal remainder of highway drive
Full A/C, coldest setting, entire trip



IMPRESSION-

It didn't act inconsistent like last trip....it went up when you expect it could/would.

Didn't go as high as last trip, despite higher air temp and more city/slow driving


Thoughts?? New fan clutch, fan blade, and new thermostat...did they help?
.
.

[wintermute]

Sharing my recent experiences here, for the record. I was having intermittent overheating issues usually traveling uphill or when stopped in traffic so I went through the entire cooling system eventually replacing the water pump, thermostat, radiator and all hoses, and the fan clutch assembly. My problem persisted. Driving up a hill, the temperature gauge would climb from below the half-way point to just shy of the H line...

I ended up finally replacing the engine coolant temperature sensor and haven't had the problem since on the same routes.

This sensor is cheap, and easy to replace. Entire job took less than 5 minutes, and doesn't require a coolant drain. Something to consider if you find yourself trouble-shooting a heat problem.

[VXorado]

My test run today was kind of inconclusive....:_thinking


Normal with full A/C all the way down, 80 miles at 70-75mph, air temp 104, full sun, in Phoenix.:eek:
City driving, stop/go, for about 20 minutes ->normal
Turned off while in restaurant 45 mins
Sat in car 5 mins, full A/C full, waiting for steering wheel to cool down --> Normal
Minutes later, driving around shopping center slowly --> Started to go up, between 70-75% of dial.
Continued slower city driving a few miles, --> Stayed around 70%-75%
Stopped for 25 mins, engine off
Started up and was at 65%
Freeway at 65mph for a few miles --> Normal
Stopped for 30 mins, engine off
Started up and was at 65%
Highway for 80 miles, 65mph --> Normal within a few mins
Climbing the steep elevation part of route--> Normal for 2/3 of 4 miles
Went up to 65%
Returned to normal remainder of highway drive
Full A/C, coldest setting, entire trip



IMPRESSION-

It didn't act inconsistent like last trip....it went up when you expect it could/would.

Didn't go as high as last trip, despite higher air temp and more city/slow driving


Thoughts?? New fan clutch, fan blade, and new thermostat...did they help?
.
.

Sorry I missed this thread & your question Sue. I may have mentioned before on an earlier thread but an OEM fan clutch with the original fan blade fixed my over heating issues. My engine temp acted exactly like yours until last April when I picked up an OEM fan clutch. I was cranking the A/C on Cliff Hanger while you were on Top of The World and my temp never moved from the normal operating temp.

I previously tried several aftermarket fan clutches, electric fan, & the coolant temp sensor Wintermute mentioned (agree it's very easy & cheap to replace).

My suggestion... try running your new OEM fan clutch with the original fan blades. You should be able to hear the fan slighlty more than the engine during accleration -at least that's how my setup sounds.

[ZeroSix]

Where is the coolant sensor located? TIA

[Chopper]

That OEM radiator is a stock GM unit. Same item is in 6cyl GM trucks and I'd suspect, in a few cars too

[wintermute]

Where is the coolant sensor located? TIA

Page 1211 of the shop manual. (Section 6E-442)

http://www.vehicross.info/gallery/showphoto.php/photo/23326

http://www.vehicross.info/gallery/showphoto.php/photo/23326

[ipd]

Add me to this list. I was running with the windows down & the heater BLASTING on the way back to Phoenix from California last night. A/C works great most of the time, but it becomes impotent when the temp gauge is pegging. By the time I got back & parked it, I could hear BOILING coming from the overflow tank--it was about 2 hours after dark & the A/C hadn't been on for at least an hour. I had topped off the coolant overflow tank before I left.

It gets WAY worse in town & with stop/go than on the highway. I tried babying it back here as much as I could--I hope I didn't do any damage to it. I'm not even sure where/how to proceed. I plan to flush it & pressure-wash the radiator (remove any caked-on dirt that might be obstructing airflow). Beyond that though, I'm at a loss.

Did we ever get a resolution on this? I'd rather get this nailed down in Phoenix--where there's more shops/people deal with cars overheating more often--than wait to get to SLC & have to work with a smaller market & less options.

[VX KAT]

Did you do a search? There's a few detailed threads on this, and how most solved this problem.

[ipd]

I did. I'm trying to piece everything together. So is the general recommendation the RD radiator, the newer-spec OEM fan clutch, and the original-spec OEM blades? Is this the "magic combo"?

And my apologies. There's YEARS of overheating issues in threads all over. Plus NONE of the links to other parts of the forum (in threads) work for me...so I have to manually search everything and cross my fingers. :(

[VX KAT]

The Admin said some things aren't working yet on this updated version.

If you've tried replacing the thermostat, relacing or flushing the radiator, and still not resolved, most (including myself) found the fan clutch was the solution. I recall VXorado bought an aftermarket one that didn't work out or died soon, so then got an OEM and it solved his problem. I also recall some strongly recommend against flushing radiator as it will flush out things that may be plugging a small hole, and the radiator may start leaking.

You can test your fan clutch by spinning it and seeing if there's resistance, but I can't recall which way it's supposed to be.

We never did figure out what benefit the redesigned fan blade served.

Some have tried adding electric fans, but most have found that didn't work either, even though it seems it should. I recall there's one owner that has had great success with his electric fan, but I think he's the only one, and several others removed them.

One other point, one or two owners found the fan blade was installed backwards...so at least check that.

[ipd]

Main fan spins about 1/2 turn after i spin it.

[ipd]

Took it out today for some small trips, stop & go, etc. Came up to middle temp range VERY fast, but stayed there--didn't budge. Even with A/C on full blast, didn't move from center. I dunno. Wife thinks the trip across the desert yesterday. Taking it to a shop for a full shakedown this week, hopefully.

Thanks for the help so far.

[Triathlete]

Mine was overheating in stop and go traffic and at slow speeds down here in Tucson. I replaced the fan clutch last week with a new one from autozone. No more overheating issues. Easy 30 minute job with basic tools.

[ipd]

Had the coolant flushed today & the fan clutch replaced. No issues yet. Knock on wood.

[ipd]

Well it seems I'm back to square one. Overflow tank is boiling again. Was only bubbling sometimes, but steam was coming out of it tonight when I parked it. Drove fine from AZ up to UT without issue. Had an oil change & I think they may have added coolant in the process. I'm really not sure what's causing it though. Oil level still reads fine. I'm at my wits end.

[Y33TREKker]

Well it seems I'm back to square one. Overflow tank is boiling again. Was only bubbling sometimes, but steam was coming out of it tonight when I parked it. Drove fine from AZ up to UT without issue. Had an oil change & I think they may have added coolant in the process. I'm really not sure what's causing it though. Oil level still reads fine. I'm at my wits end.
Have you ever changed your radiator cap? The purpose of a properly operating cap is to increase the pressure in the radiator/cooling system to allow the coolant to reach it's designed boiling point.

What is your coolant level in the radiator itself with the radiator cap off and the engine running at normal operating temps (the coolant/engine hot enough to open the thermostat)? It should be up near the top of the tank when looking into the radiator cap opening. I wouldn't just trust what the reservoir level is telling you anyway since you may have an air pocket elsewhere in the engine.

You could also try adding the aftermarket product Water Wetter. It increases the surface tension of whatever coolant you're running, effectively increasing it's boiling point.

I'd have my doubts that you have a head gasket issue if the engine so far has been running evenly, but you could always have your cooling system pressure checked (with one of the gauges that installs where the radiator cap usually goes) to determine if you have any air leaks in the cooling system.

[ipd]

Just got off the phone with the shop. They said they could find NOTHING amiss, apart from air in the coolant system--which they bled out. Given that the car ran just fine from Phoenix to SLC--no temp issues--I can only assume that it must have stemmed from the quickie-lube shop cracking the cap on the radiator to "fill er up". I'm still new to the VX. Is this engine an odd type of configuration that requires special handling to prevent air from entering the coolant system?

For the record, the Head Gasket was replaced about 1k prior to me buying this VX, and the Cap was replaced & the coolant was flushed--back in Phoenix.

This is the 2nd time I've been told--since arriving in SLC--that the coolant was low. Once by the quickie lube place who poured coolant directly into the radiator (I didn't see them doing it until it was already underway), and once by the shop who bled the system. What I'm confused on is whether I actually have a leak or not. If I have a leak, then that would explain the coolant being "low" but not why I was able to drive it successfully for 12+ hours of road travel without issues (because a leak would mean I couldn't pressurize the system, and therefore would overheat).

[Y33TREKker]

Just got off the phone with the shop. They said they could find NOTHING amiss, apart from air in the coolant system--which they bled out. Given that the car ran just fine from Phoenix to SLC--no temp issues--I can only assume that it must have stemmed from the quickie-lube shop cracking the cap on the radiator to "fill er up". I'm still new to the VX. Is this engine an odd type of configuration that requires special handling to prevent air from entering the coolant system?

For the record, the Head Gasket was replaced about 1k prior to me buying this VX, and the Cap was replaced & the coolant was flushed--back in Phoenix.

This is the 2nd time I've been told--since arriving in SLC--that the coolant was low. Once by the quickie lube place who poured coolant directly into the radiator (I didn't see them doing it until it was already underway), and once by the shop who bled the system. What I'm confused on is whether I actually have a leak or not. If I have a leak, then that would explain the coolant being "low" but not why I was able to drive it successfully for 12+ hours of road travel without issues (because a leak would mean I couldn't pressurize the system, and therefore would overheat).
It could just be that with an air pocket in the system, an accurate reading from the reservoir couldn't be determined. This is referred to in the following procedure from the VX manual.

http://www.vehicross.info/gallery/uploads/586/VX_radiator_refill.JPG

It also has to be remembered that the transmission cooling is handled by the trans line coils in the radiator, so if you're pushing the VX/transmission hard, that puts more cooling load on the radiator besides just the heat being generated by the engine.

[ipd]

Took it out for a long drive today. Not one issue. I've been researching this even more, and it appears to be a fairly common problem caused by idiot mechanics doing similar "top off" things. I've never had this type of issue with my other vehicles, so I'll be keeping a hawkish eye on it to make sure no 2-bit mechanic pops open the radiator cap. Ever.

[Y33TREKker]

Took it out for a long drive today. Not one issue. I've been researching this even more, and it appears to be a fairly common problem caused by idiot mechanics doing similar "top off" things. I've never had this type of issue with my other vehicles, so I'll be keeping a hawkish eye on it to make sure no 2-bit mechanic pops open the radiator cap. Ever.
If I had to guess, I'd say that any overfilling by such mechanics takes place just because they are under so much pressure to get the job done so fast, so they pour as much in as fast as they can.

Some vehicle manufacturers account for the possibility by having a plug in the thermostat housing that can be removed to allow air to escape during the filling process, although my daily driver even has a second "radiator" cap near the thermostat housing that allows me to open the system there to let air escape and add coolant once the car has been running for a few minutes and the thermostat has opened.

Unfortunately, the VX's cooling system has neither of those options, so you just have to do it old school and do all of the coolant filling and top-offs at the radiator inlet itself.

The key is to let the engine get to operating temps (hot enough that the thermostat has opened and coolant is flowing from the engine to the radiator), observe the level of the coolant in the radiator inlet, and add accordingly at that point.

[ipd]

Final update....hopefully.

Had the head gasket replaced. According to the Mx receipts from the previous owner/s, the head gasket was done previously--but it might not have been done up to snuff. 2 different shops confirmed hydrocarbons in the coolant--so it was a sure thing. Water pump is in pristine condition, which is evidence that it had been changed recently. Biggest question-mark was the head bolts, as the shop indicated that these had apparently stretched. It is not known if these were pushed by head gasket pressure, or if they were faulty previously and not replaced during the last attempt at this repair. It does come with a 12 month 12,000 warranty, so I expect to be driving the piss out of it this summer with the A/C on full blast--just to "stress-test" it to verify that I'm not still getting issues with it. (Hard to tell when I'm doing 15-20m trips and it's 15 F outside).

I'll also be religiously checking my oil levels, as I may now start to see oil consumption (although I noted none previously). What still unsolved is how I got it from SD to Phoenix and finally to SLC without having a catastrophic breakdown.

[Y33TREKker]

Glad to hear the of the more detailed diagnosis and that the issue is, hopefully, resolved.

I'm sure the new head gaskets and head bolts will help and offer more peace of mind.

[eternal21]

Got the new fan clutch, fan blade and thermostat installed.
Merlin advised a redesigned OEM fan clutch is the only one available now, and requires a new fan blade as well. New fan clutch is now $250 and blade $100...:eek: OUCH! Old fc was around $70 IIRC....:(

http://www.vehicross.info/gallery/data/500/DSCN5263.JPG

http://www.vehicross.info/gallery/data/500/DSCN5728.JPG

If you order this part from Isuzuparts.com, you need to specify the part number. If you have the new fan clutch (part number 8-97349-761-0) DO NOT order online as they will send you the old fan (part number 8-97172-201-0, bottom picture above). When I had to call them after ordering online because they sent me the wrong fan, the guy I spoke to (Brian) said that the new fan doesn't even show as a part for the VehiCROSS. Just as an FYI, the redesigned fan part number is 8-97349-762-0, top picture above).

The old fan/new fan clutch are physically incompatible.

[Nikad92397]

Seems to me that there is another problem.
People have tried all sizes of radiators,
All sizes of fans, all kinds of combinations of ideas and they all point to one thing. Air flow.
Hood scoops help, stock or updated clutch and fans work. Everything else should help but it doesn't.

I was out in Barstow a few weeks ago and in deep sand washes littered with rocks I started getting to the
Big H on my gauge. It was 112 degrees out and who knows how hot in the washes (yes my A/C was on)
I sped and put it in park and just sat there with my foot holding the gas peddle to a fast idle and it cooled down to just before half way on the gauge. Sounding like a airplane stuck in the mud, A/C still on.

I kept thinking of all these posts and my brain kept coming up with air flow. I couldn't cut the hood in nowhere land, couldn't check all there other things out in the bush so I pulled the grill off, my temp never left 1/2 way on my gauge for the rest of the day, air flow. Hummmm. Anyone else ever pull their grill off and try it ? Worked for me so I made a summer grill.
Seems to be working.

[Nikad92397]

http://www.vehicross.info/gallery/data/500/thumbs/image25.jpeg ('http://www.vehicross.info/gallery/data/500/image25.jpeg')