Burning Oil?

[psychos2]

It is not so much the fault of the pcv valve as it is the fact that there is no baffle to stop the oil from being sucked from the valve cover. In other engines the failure of the pcv valve does not have the same affect as it does in the 3.5 . shawn

[Jolly Roger VX'er]

My own personal experience has taught me that there was a double-edged sword involved with oil consumption in my engine.

The EGR Valve..if not properly recirculating exhaust gases back into the cylinders to be reburned (EGR=Exhaust Gas Recirculation) under normal operation, would lead to higher cylinder temps. Just like if you were to block it off and deny proper operation.

When the EGR is functioning properly, it is "smothering" the cylinders with spent exhaust gas that is meant to be reburned for environmental sake and therefore not letting in a totally fresh air/fuel mixture during the intake stroke. In effect...it is lowering the efficiency of each cylinder. Make the EGR inoperable either through failure (ie.stuck closed) or physically blocking it off and the cylinder temps go up due to the more efficient combustion of a fresh air/fuel intake charge not being smothered by exhaust gasses fed into the cylinders through the intake by the EGR.

Then...add in a malfunctioning PCV which leads to high crankcase pressure that "resists" the oil in the cylinder attempting to return back to the oil pan.

Now that you have oil lingering around in the cylinders due to opposing pressure of a stuck PCV and higher cylinder temps due to a stuck EGR you get alot of oil burn-off during the combustion process.

In short...My VX started using oil before I supercharged it at 30,000 miles; and after I cleaned out the EGR with oxgen sensor safe carb cleaner to remove the black carbon that was causing it to stick closed....and after I started changing the PCV at regular intervals to maintain proper operation....the oil usage dropped drastically to what I consider normal (approx. 1/4 quart in 3,000 mile oil change interval....sometimes less)

I recommend cleaning the EGR @ 30,000 mile intervals...or replacing it if cleaning it doesn't free up a stuck valve. I recommend maintaining proper operation of the PCV.

If there is an oil ring problem..it will only be exaggerated by the failures of either the EGR and/or the PCV systems....think of all this as a triangle...where you have control over 2 of the 3 legs.

[Jolly Roger VX'er]

This has been a presentation of "Your internal combustion engine & you, the early years"...

ouch...your making me experience flash-backs of a black & white 8mm tape reel movie on an old projector with some monotone sounding guy chirping away making my eyelids real droo---oooo---pppie...zzzzzzzzzzzzzzzzzz

[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.

[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.

[Gussie2000]

My own personal experience has taught me that there was a double-edged sword involved with oil consumption in my engine.

The EGR Valve..if not properly recirculating exhaust gases back into the cylinders to be reburned (EGR=Exhaust Gas Recirculation) under normal operation, would lead to higher cylinder temps. Just like if you were to block it off and deny proper operation.

When the EGR is functioning properly, it is "smothering" the cylinders with spent exhaust gas that is meant to be reburned for environmental sake and therefore not letting in a totally fresh air/fuel mixture during the intake stroke. In effect...it is lowering the efficiency of each cylinder. Make the EGR inoperable either through failure (ie.stuck closed) or physically blocking it off and the cylinder temps go up due to the more efficient combustion of a fresh air/fuel intake charge not being smothered by exhaust gasses fed into the cylinders through the intake by the EGR.

Then...add in a malfunctioning PCV which leads to high crankcase pressure that "resists" the oil in the cylinder attempting to return back to the oil pan.

Now that you have oil lingering around in the cylinders due to opposing pressure of a stuck PCV and higher cylinder temps due to a stuck EGR you get alot of oil burn-off during the combustion process.

In short...My VX started using oil before I supercharged it at 30,000 miles; and after I cleaned out the EGR with oxgen sensor safe carb cleaner to remove the black carbon that was causing it to stick closed....and after I started changing the PCV at regular intervals to maintain proper operation....the oil usage dropped drastically to what I consider normal (approx. 1/4 quart in 3,000 mile oil change interval....sometimes less)

I recommend cleaning the EGR @ 30,000 mile intervals...or replacing it if cleaning it doesn't free up a stuck valve. I recommend maintaining proper operation of the PCV.

If there is an oil ring problem..it will only be exaggerated by the failures of either the EGR and/or the PCV systems....think of all this as a triangle...where you have control over 2 of the 3 legs.

I got to agree with you about this one,my mech told the same thing as you explained here.

The PCV should be replace every oil change just for the sake of the engine.

In february i'll have my VX's transmission,transfer case & differential fluids serviced & i'll probally have the EGR cleaned so make sure full performance is delivered

[psychos2]

I got to agree with you about this one,my mech told the same thing as you explained here.

The PCV should be replace every oil change just for the sake of the engine.

This is all good as long as the pcv valve functions properly for 3000 miles. I had a brand new one malfunction and lost 2 qts of oil in the first 1000 miles After an oil change and pcv valve change. If I had not checked the oil level before leaving on a 3 hr trip to NH I would have had a seized motor.

Also I would have to disagree with this statement:
"Then...add in a malfunctioning PCV which leads to high crankcase pressure that "resists" the oil in the cylinder attempting to return back to the oil pan.

Now that you have oil lingering around in the cylinders due to opposing pressure of a stuck PCV and higher cylinder temps due to a stuck EGR you get alot of oil burn-off during the combustion process."

There should be no oil in the cylinder trying to return to the pan. Any oil that gets past the rings or is sucked in through the pcv valve will not return to the oil pan it gets burned. Or do you mean the oil in the crankcase below the piston on the cylinder wall ? shawn

[iamironman]

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






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[Jolly Roger VX'er]

There should be no oil in the cylinder trying to return to the pan. Any oil that gets past the rings or is sucked in through the pcv valve will not return to the oil pan it gets burned. Or do you mean the oil in the crankcase below the piston on the cylinder wall ? shawn

Absolutely true...if excessive enough gives you the tell-tell bluish smoke out the exhaust pipe (worn rings)

Yes, I was meaning the oil in the crankcase below the piston on the cylinder wall that could be opposed by high crankcase pressure to return to the pan and be subjected to the high volitility (burn-off) of elevated cylinder temps due to malfunctioning EGR. Sorry, I should have stated it better than I did.

[ilya]

Hi, car guy here, has anyone put in aftermarket pistons or tried to swap in the newer style piston from the 02 or 04 engine in hopes of solving this?

[Gussie2000]

Hi, car guy here, has anyone put in aftermarket pistons or tried to swap in the newer style piston from the 02 or 04 engine in hopes of solving this?

HI Ilya !

Absolutely ! many VX'ers had their engines rebuildt or completly replaced.

I personally have no idea if aftermarket rings is a good deal to go for,however i'll suggest you to do some research & figured out two tips:


COST AGAINS VALUE AGAINS QUALITY

If a set of original OEM pistons from isuzu cost $ 350 & the aftermarket set cost $ 280 i'll try to put the other $ 70 & buy the original .....This is my quote

[kodiak]

As far as I know it’s not the pistons or rings that’s causing the oil consumption problem.

Hi, car guy here, has anyone put in aftermarket pistons or tried to swap in the newer style piston from the 02 or 04 engine in hopes of solving this?

[TheGanzman]

As far as I know it’s not the pistons or rings that’s causing the oil consumption problem.

http://www.isuzuforums.com/forum_posts.asp?TID=1877

[Junster]

Hoping for an answer to the "rebuild using 2002/04 pistons and rings" any info on this? I have fallen off the deep edge and will have a VX soon. I tend to keep a vehicle a long time. So a engine rebuild is almost always somewhere in it's future. Thanks

[VX KAT]

Hoping for an answer to the "rebuild using 2002/04 pistons and rings" any info on this? I have fallen off the deep edge and will have a VX soon. I tend to keep a vehicle a long time. So a engine rebuild is almost always somewhere in it's future. Thanks

Here's several threads on oil consumption, theories of what causes the problem, engine failure, polls, experience, etc... Might help you decide on whether it's the pistons, or better to rebuild or replace with an Axiom engine.

Several theories on Isuzu design defect in rings that causes oil consumption:
http://www.vehicross.info/forums/sho...rand+pcv+valve

http://vehicross.info/forums/showthr...E+FAILURE+POLL

http://vehicross.info/forums/showthr...E+FAILURE+POLL

http://vehicross.info/forums/showthr...ngine+oil+poll

http://vehicross.info/forums/showthr...184#post166184

http://www.vehicross.info/forums/sho...light=axiom+DI

http://www.vehicross.info/forums/sho...light=axiom+DI

http://vehicross.info/forums/showthr...ght=iamironman

Here's the thread from Iamironman...
http://www.vehicross.info/forums/sho...ght=built+2000

http://www.vehicross.info/forums/sho...ine+swap+axiom


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