FYI for those people with overheating issues with their VX

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.

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Originally Posted by 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?
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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.

Where is the coolant sensor located? TIA

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

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Originally Posted by ZeroSix

Where is the coolant sensor located? TIA

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

http://www.vehicross.info/gallery/sh...hp/photo/23326

http://www.vehicross.info/gallery/sh...hp/photo/23326

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.

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

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. :(

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.

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

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.

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.

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

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.

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Originally Posted by 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.

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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.