Burning Oil?

[nfpgasmask]

Another opinion here, if you are getting a CEL, I would try to get the code read so you know what the issue is. It could very easily be a stuck EGR valve....

Bart

[Jolly Roger VX'er]

the PCV valve ($3-5.00), should be changed every other oil change.

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!

[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.

[psychos2]

My mechanic who's an former isuzu engine specialist told me that isuzu engineers oversight the facts that the ducts the oil runs throughtout the engine were too big & too few of them so a considareble amount of oil goes into the combustion chamber which shouldn't be happening,specially on high RPM's situations such as be in the highway or express ways when the oil pump pumps high amounts of oil as per demanded by the engine.

This problem is found in almost all 1998 to 2001 engines my mech told me,he had more that 200 isuzu troopers,rodeos & 2001 axioms just in his shop & about 3 vehicross (included mines) which had a few sticky lifters due the lack of use.

1st , most of the oil consumption issues are pcv valve related. There is no baffle in the valve cover to keep the oil away from the pcv valve and when it sticks open the oil is sucked into the intake and burned. Has nothing to do with oil passages. Had it happen to me I was using 1 qt per 3000 miles ,when the pcv valve stuck I used 2 qts in 1000 miles. I no longer have a pcv valve. back to 1 qt per 3000 miles.And no worries about when it the pcv valve will stick again.

2nd ,there is no way any vx with a 3.5 has stuck lifters. they do not have any. They have the camshaft in the head directly above the valves, I believe it is called a direct attack setup. No lifters ,no rocker arms.

also in 2002 they came out with the direct injection 3.5 which has more hp because the fuel is injected directly into the cylinders. I believe this engine is not a direct swap and you would have to change the wiring harness and computer.
I am in no way trying to start anything just correcting incorrect info. shawn

[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...

[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.

[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 !

[Gussie2000]

1st , most of the oil consumption issues are pcv valve related. There is no baffle in the valve cover to keep the oil away from the pcv valve and when it sticks open the oil is sucked into the intake and burned. Has nothing to do with oil passages. Had it happen to me I was using 1 qt per 3000 miles ,when the pcv valve stuck I used 2 qts in 1000 miles. I no longer have a pcv valve. back to 1 qt per 3000 miles.And no worries about when it the pcv valve will stick again.

2nd ,there is no way any vx with a 3.5 has stuck lifters. they do not have any. They have the camshaft in the head directly above the valves, I believe it is called a direct attack setup. No lifters ,no rocker arms.

also in 2002 they came out with the direct injection 3.5 which has more hp because the fuel is injected directly into the cylinders. I believe this engine is not a direct swap and you would have to change the wiring harness and computer.
I am in no way trying to start anything just correcting incorrect info. shawn

By the way i replace the PC valve the day i had my VX oil change the 1rst time,still oil compsumtion keeps happening,so no,oils goes into the combustion chamber & burn,the piston rings were manufactured with wrong specs,that's exactly what the mech was explaining me;I'll print your intup & take it to him so let's see who could be wrong.

[psychos2]

By the way i replace the PC valve the day i had my VX oil change the 1rst time,still oil compsumtion keeps happening,so no,oils goes into the combustion chamber & burn,the piston rings were manufactured with wrong specs,that's exactly what the mech was explaining me;I'll print your intup & take it to him so let's see who could be wrong.

I am sorry but you did not say that re read your post! I have had issues with the pcv valve, and that is that. I still lose 1 qt every 3000 miles , and would consider that normal. When the pcv valve sticks and I lose 2 qts in 1000 miles that is not normal. And doing what I have done to get rid of the pcv valve has brought it back to 1 qt every 3000 miles and that is fact , not what someone told me. So I do not care if your mechanic says I am wrong I know that my problem is fixed . And be sure to print out your post and ask him if that is what he said. shawn

[Gussie2000]

I am sorry but you did not say that re read your post! I have had issues with the pcv valve, and that is that. I still lose 1 qt every 3000 miles , and would consider that normal. When the pcv valve sticks and I lose 2 qts in 1000 miles that is not normal. And doing what I have done to get rid of the pcv valve has brought it back to 1 qt every 3000 miles and that is fact , not what someone told me. So I do not care if your mechanic says I am wrong I know that my problem is fixed . And be sure to print out your post and ask him if that is what he said. shawn

Ok,let's not get passionate about this one my fellow VXer,i quite sure this issue has been on the table many times.

However i use the word lifters to explain my self somehow & the mechanic just brief me about the oil compsumtion & the experience he had in the past & what can be the possible reasons the engine's burning oil.

My warranty covered all the cost,i just went & drove off out the shop.

Yes,it's normal to have some sort of oil loss between oil changes,we all agree in this one.

I believe that if the PCV wasn't necessary for all modern engines then why is there for ? probally i'll follow you on the PCV issue & get rid off it so i may be able to loss less oil as you do.But my VX doesn't burn as much as 1 Qt every 2000 miles

The noise i had in my engine was the tipical ticking noise,right at the top of the engine,my mech solve the problem & the engine runs as quiet as you can imagine the work is covered with 50.000 miles or 5 years.

I regret not to step by at the shop & had a look at the open engine so i can gain more knowledge about how the isuzu 3.5L engine works.

Plus your input was refered in your personal experience agains my mechanic.Your believe the problem was solve by getting rid of the PCV,my problem can be the rings or otherwise,who knows.

What the mech meant afterall is that isuzu fail to support its customers by ignoring the issue,they turn their back on you,me & all the rest of us whom purchased their products.

I not sure,but i think the engine you are talking about is the 2004 3.5L with the direct injection system that came with the axioms which really needs the ECU software upgrade & the wiring harness replaced if you want it in the VX

If i had the opportunity i'll deffinetly drop a 2004 engine into the VX.

[Ldub]

Ok,let's not get passionate about this one my fellow VXer,i quite sure this issue has been on the table many times.

However i use the word lifters to explain my self somehow & the mechanic just brief me about the oil compsumtion & the experience he had in the past & what can be the possible reasons the engine's burning oil.

My warranty covered all the cost,i just went & drove off out the shop.

Yes,it's normal to have some sort of oil loss between oil changes,we all agree in this one.

I believe that if the PCV wasn't necessary for all modern engines then why is there for ? probally i'll follow you on the PCV issue & get rid off it so i may be able to loss less oil as you do.But my VX doesn't burn as much as 1 Qt every 2000 miles

The noise i had in my engine was the tipical ticking noise,right at the top of the engine,my mech solve the problem & the engine runs as quiet as you can imagine the work is covered with 50.000 miles or 5 years.

I regret not to step by at the shop & had a look at the open engine so i can gain more knowledge about how the isuzu 3.5L engine works.

Plus your input was refered in your personal experience agains my mechanic.Your believe the problem was solve by getting rid of the PCV,my problem can be the rings or otherwise,who knows.

What the mech meant afterall is that isuzu fail to support its customers by ignoring the issue,they turn their back on you,me & all the rest of us whom purchased their products.

I not sure,but i think the engine you are talking about is the 2004 3.5L with the direct injection system that came with the axioms which really needs the ECU software upgrade & the wiring harness replaced if you want it in the VX

If i had the opportunity i'll deffinetly drop a 2004 engine into the VX.

The PCV (Positive Crankcase Ventilation) valve, came about sometime in the sixties IIRC, it was a measure taken in an effort to reduce air pollution.
Before that, excess crankcase pressure was vented into the atmosphere through "breathers", either on the valve covers, or sometimes through the oil fill cap...

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