Isolating Oil Burning Cause
09-25-2011, 01:05 PM
#1
Isolating Oil Burning Cause
So, I'm running into a very sudden oil burning issue and I'd like some thoughts on how to narrow down where it's getting in. First of all, it's only doing it when the car (2003) is hot. Once it's hot, if you idle at a traffic light, it will smoke a bit during idle and then let out a pretty embarrassing cloud when you take off. I could go wide open throttle after that and it won't let out a puff.
It will also let out quite a bit if I use the tranny to decelerate down a hill and then hop on the gas. If I'm not mistaken, I believe this indicates that it is likely the valve seals, as opposed to the rings or valve guides. Do you agree? What else can I do to conclusively determine where the oil is getting in?
The car has under 60,000 miles on it and it's been treated quite well so I'm not inclined to believe that it could be rings or something requiring a major rebuild.
The only other new thing in play is test pipes. I slapped them on about a month ago for ***** and giggles and since then I've done an autocross and gone on a road trip where I sustained very high speeds up/over mountains for a long time. (Probably 90+% throttle for over an hour... I really worked it hard!) There were no smoking issues until I returned home from the road trip. The car has had the test pipes on for over 2,000 miles. It is not burning grease off of the test pipes and it is not burning some sort of packing/deadening material out of them. It is burning oil.
I'm about to go check the PCV valve. If it's not the problem, I may put the cat's back in on the off chance that there is some of the famous "back pressure" thing that causes the valve seals to leak. I intend to do a leak-down test at some point but I would like to make myself one of those since they don't seem too complicated and I haven't seen one at any of my local stores, yet.
Cliff Notes:
1. Burns oil only when hot.
2. Only after deceleration or idling.
3. Somewhat recent test pipes and recently driven very hard.
4. Sounds like valve seals to me. What do you think?
It will also let out quite a bit if I use the tranny to decelerate down a hill and then hop on the gas. If I'm not mistaken, I believe this indicates that it is likely the valve seals, as opposed to the rings or valve guides. Do you agree? What else can I do to conclusively determine where the oil is getting in?
The car has under 60,000 miles on it and it's been treated quite well so I'm not inclined to believe that it could be rings or something requiring a major rebuild.
The only other new thing in play is test pipes. I slapped them on about a month ago for ***** and giggles and since then I've done an autocross and gone on a road trip where I sustained very high speeds up/over mountains for a long time. (Probably 90+% throttle for over an hour... I really worked it hard!) There were no smoking issues until I returned home from the road trip. The car has had the test pipes on for over 2,000 miles. It is not burning grease off of the test pipes and it is not burning some sort of packing/deadening material out of them. It is burning oil.
I'm about to go check the PCV valve. If it's not the problem, I may put the cat's back in on the off chance that there is some of the famous "back pressure" thing that causes the valve seals to leak. I intend to do a leak-down test at some point but I would like to make myself one of those since they don't seem too complicated and I haven't seen one at any of my local stores, yet.
Cliff Notes:
1. Burns oil only when hot.
2. Only after deceleration or idling.
3. Somewhat recent test pipes and recently driven very hard.
4. Sounds like valve seals to me. What do you think?
09-25-2011, 02:33 PM
#2
Registered User
After running a stock engine with 60K miles at 90% for an hour, the fact that it'll run at all is impressive.
I'd go with intake valve guides/seals as the cause based on symptoms given. The long hard run may have starved them of oil, since they weren't subjected to the low pressure which pulls just enough oil through the seals to keep them and the guides lubed.
I'd go with intake valve guides/seals as the cause based on symptoms given. The long hard run may have starved them of oil, since they weren't subjected to the low pressure which pulls just enough oil through the seals to keep them and the guides lubed.
09-25-2011, 06:14 PM
#3
I mean, surely a Matrix or some other EconoBox spends more time at full throttle just maintaining the speed limit. Anyway, it's not like I ran it up Pikes Peak 10 times or something that crazy, but I did not go easy on it.Are you aware of a method to determine whether it's the seals or the guides without pulling the heads apart? I know that the seals are no picnic, but the heads will have to be removed if it's the guides, right?
Thanks for your help!
10-01-2011, 11:57 AM
#4
So, I just checked the PCV as per the factory service manual and it appears to be functioning correctly. What would you folks do next?
1.) Put the cat's back on.
OR
2.) Leak down test.
There are a fair number of threads mentioning smoking after test pipe installs. I looked at a few of them and I can't see how it would cause smoking unless it was black/grey exhaust coming through that didn't get reacted out through the cat's. Mine is fairly conclusively burning oil, so I would like to narrow down the source.
1.) Put the cat's back on.
OR
2.) Leak down test.
There are a fair number of threads mentioning smoking after test pipe installs. I looked at a few of them and I can't see how it would cause smoking unless it was black/grey exhaust coming through that didn't get reacted out through the cat's. Mine is fairly conclusively burning oil, so I would like to narrow down the source.
Last edited by DaveJackson; 10-02-2011 at 01:15 PM. Reason: grammmerr gooder
10-01-2011, 03:26 PM
#5
Registered User
The cylinder leak-down test only tells you the condition of the valve-to-valve seat seal and the rings-to-cylinder seal at top dead center. It won't tell you anything about the valve stem seals, which is probably where the problem is.
A regular compression test will tell you something about the condition of the rings over the full stroke, so that might be more useful. But keep in mind that valve seat leakage can make the readings low, too. Unfortunately, it also won't tell you anything about the valve stem seals.
A regular compression test will tell you something about the condition of the rings over the full stroke, so that might be more useful. But keep in mind that valve seat leakage can make the readings low, too. Unfortunately, it also won't tell you anything about the valve stem seals.
10-03-2011, 07:23 AM
#6
I did the leak down test (warm) and all cylinders are great with less than 15% leakage. So, I assume that this either means valve seals, or possibly valve guides. Is there a way to determine if it's guides? I would hate to go to the hassle of changing seals and then find out it was guides!
Only other thing is one of the plugs was oil-fouled. And, I mean on the firing surface, not in the sealing area where the coil packs fit on. I was sure this cylinder would fail the leak down test, but it was fine.
Only other thing is one of the plugs was oil-fouled. And, I mean on the firing surface, not in the sealing area where the coil packs fit on. I was sure this cylinder would fail the leak down test, but it was fine.
Last edited by DaveJackson; 10-03-2011 at 07:25 AM.
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10-03-2011, 07:46 PM
#8
First I wished it was oil, then I wished it was the PCV valve but no luck.
After that, in the back of my mind I almost started wishing it was rings so I could say, "Alright, screw this!! I am rebuilding this thing with low-comp pistons and forged rods and definitely getting a Boosted Performance turbo kit!"
Then I wished it was test pipes, and finally I was forced to wish it was "only" valve seals.
That's where it stands now, unless someone else can tell me if it might be valve guides.
Anyone???
06-13-2015, 10:23 AM
#11
I haven't seen leaks on mine but there definitely burning going on bc by the time I go over 1k mobile 1 5w 30. I have to add about 2 bottles to keep it above the empty mark on the dip stick. So I am not sure if it's worth to fix it or just keep adding got seat down and do the math what you guys think thanks for any input
07-08-2015, 12:54 PM
#12
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Has anyone made any headway with this issue? I have the exact same problem with my 04 with 155k miles. Happened after a 4 hour drive doing 80 mostly. Changed pcv and have done a compression check. Compression was with in spec and the pcv didn't change anything. Testpipes installed too.
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