Burning Oil?

[Ldub]

I was following this advice until I went to Moab & a brand new PCV failed. Second time this has happened to me...first time with AutoZone brand. I took out a perfectly good one before the road trip and put in a new one only to have it (the new one from Advance Auto--Purolator) stick closed.

My engine which usually is very good on oil usage (like 1/4 quart in 3,000 miles) sucked up one quart out of the blue. Caught it when I refueled & checked oil. Than saw oil spray coming out of my breather cap (aftermarket).

My new approach is to just leave a functioning one in and check periodically for any oil spray from breather cap & check dipstick @ fuel stops plus when putzing under the hood. It looks like my set-up allows the excess crankcase pressure to exit out the breather cap (if PCV is stuck) when normally it would be sucking air into the breather cap. I'll carry a spare PCV from now on and be reactive instead of proactive!

Good point, I've had a purolator seperate before (top & bottom came apart), but I still like em', IMO, there will be occaisional defects in any brand.

Another thing you can do, is clean em' out with carb/TB cleaner & keep em' as a spare.

[Jolly Roger VX'er]

Good point, I've had a purolator seperate before (top & bottom came apart), but I still like em', IMO, there will be occaisional defects in any brand.

Another thing you can do, is clean em' out with carb/TB cleaner & keep em' as a spare.

I still have the one I bought in Moab (like $12...ouch...but if it lasts it was worth it!!!!) that was a brand I never heard of (sold at one of those Mom & Pop Parts stores!) and it works like a champ..rattles properly when checked...no problems! I figure I'll just keep an eye on it.

Plus, I did have good luck with the PCV sold @ NAPA in the past, but only used that brand twice. It was made in USA and cost like $8.

I still remember the old days..lol..I had a '69 Plymouth Roadrunner and the only pollution control was a PCV...and it was made out of stamped steel with a steel ball bearing inside...NOW that sucker was good for 40+ years I'd bet!!!!!!!

[Ldub]

I still have the one I bought in Moab (like $12...ouch...but if it lasts it was worth it!!!!) that was a brand I never heard of (sold at one of those Mom & Pop Parts stores!) and it works like a champ..rattles properly when checked...no problems! I figure I'll just keep an eye on it.

Plus, I did have good luck with the PCV sold @ NAPA in the past, but only used that brand twice. It was made in USA and cost like $8.

I still remember the old days..lol..I had a '69 Plymouth Roadrunner and the only pollution control was a PCV...and it was made out of stamped steel with a steel ball bearing inside...NOW that sucker was good for 40+ years I'd bet!!!!!!!

I was thinkin' the same thing...except get one machined out of SS or aluminium, with top & bottom halves threaded together so you could take it apart to clean...
Would last forever & co$t big bucks by comparison...a guy can dream, yah?
I miss my 70 Mustang...wasn't a "Boss" but had all the boss spoilers, rear window louver, paint scheme, ET's, Lakewood...yadda-yadda-yadda...
Can't even find a pic of it any more...

[BigSwede]

While I do think some of the oil burning is PCV related, there is another theory than the several presented here - this is what Jerry Lemond, who used to train Isuzu mechanics, told me:

The 3.5L is a stroked version of the 3.2L. Because of the deeper crankshaft necessary for the 3.5L, the pistons had to have relatively short skirts to avoid impacting the crankshaft, leaving less room for piston rings. As a result the 3.5L pistons only have one oil ring. The oil ring's job is to squeegee oil from the cylinder wall. The oil ring also has drain-back holes for any oil that gets trapped between the oil ring and the compression ring. The oil ring for the 3.5L only had 4 drainback holes, which apparently was inadequate for the job, so some of the trapped oil ends up going the other way, up into the combustion chamber and is burned.

The improved design 3.5L, identifiable by the screw-in PCV valve, has oil rings with additional drainback holes.

[shrug] I dunno which theory or combination thereof is correct, just thought I'd pass this one along. Have a nice day

[VehiGAZ]

ONE ring on each piston?!?! Can anyone confirm that?!

That would be enough to lead to oil burning as soon as the one, lonely ring loses it's state of perfection...

[BigSwede]

ONE ring on each piston?!?! Can anyone confirm that?!

That would be enough to lead to oil burning as soon as the one, lonely ring loses it's state of perfection...

No, I was saying one oil ring, which still would be in addition to the compression ring. But as was noted there are indeed 3 rings not just 2.

[psychos2]

While I do think some of the oil burning is PCV related, there is another theory than the several presented here - this is what Jerry Lemond, who used to train Isuzu mechanics, told me:

The 3.5L is a stroked version of the 3.2L. Because of the deeper crankshaft necessary for the 3.5L, the pistons had to have relatively short skirts to avoid impacting the crankshaft, leaving less room for piston rings. As a result the 3.5L pistons only have one oil ring. The oil ring's job is to squeegee oil from the cylinder wall. The oil ring also has drain-back holes for any oil that gets trapped between the oil ring and the compression ring. The oil ring for the 3.5L only had 4 drainback holes, which apparently was inadequate for the job, so some of the trapped oil ends up going the other way, up into the combustion chamber and is burned.

The improved design 3.5L, identifiable by the screw-in PCV valve, has oil rings with additional drainback holes.

[shrug] I dunno which theory or combination thereof is correct, just thought I'd pass this one along. Have a nice day

The pistons have 3 rings like any other piston. And the theory about the drain back holes would be ok if all 3.5L engines had the same oil consumption amount. shawn

[JHarris1385]

Here is my repost on this issue:

Hi John,

Its not actually oil loss that’s a problem its oil pressure loss. Where the oil filter bolts onto the engine you will see that it does not bolt directly to the block. It bolts onto a cast metal item which is attached to the block. This cast piece that sits between the block and the oil filter is one of the main problems of oil pressure loss. Inside it there is very sharp bends which restricts oil flow and therefore oil pressure.

We solve this issue by removing this cast piece and have it replaced with another fitting that allows the oil filter to be remote mounted. This will be available for purchase shortly.

The other issue is only when the engine is pulled down. The oil feed system to the main bearings comes in at the number 1 piston and travels along feeding the others. This means that the number 6 piston is the last one to get any oil fed to it and is why the number 6 bearing is prone to failure. We have a modified oil delivery system available which rectifies this problem and gives even oil flow and pressure to all main bearings.

[BigSwede]

The pistons have 3 rings like any other piston. And the theory about the drain back holes would be ok if all 3.5L engines had the same oil consumption amount. shawn

You may be right about the number of rings, I wasn't sure about that part and was going from memory of a conversation over a year ago. But the change in oil ring drainback holes is the main point and is factual. Whether it is the main cause of oil burning is another question.

I also meant to say there is an oil-burning connection with the EGR system more so than PCV. My old 99 Trooper didn't burn any oil (at least until it got totaled), which I suspected had to do with the Mobil One I used and it's tendency not to gum up the EGR system. But I have no way to prove it.

[iamironman]

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Done!!






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[Gussie2000]

While I do think some of the oil burning is PCV related, there is another theory than the several presented here - this is what Jerry Lemond, who used to train Isuzu mechanics, told me:

The 3.5L is a stroked version of the 3.2L. Because of the deeper crankshaft necessary for the 3.5L, the pistons had to have relatively short skirts to avoid impacting the crankshaft, leaving less room for piston rings. As a result the 3.5L pistons only have one oil ring. The oil ring's job is to squeegee oil from the cylinder wall. The oil ring also has drain-back holes for any oil that gets trapped between the oil ring and the compression ring. The oil ring for the 3.5L only had 4 drainback holes, which apparently was inadequate for the job, so some of the trapped oil ends up going the other way, up into the combustion chamber and is burned.

The improved design 3.5L, identifiable by the screw-in PCV valve, has oil rings with additional drainback holes.

[shrug] I dunno which theory or combination thereof is correct, just thought I'd pass this one along. Have a nice day

Thank you !