burning oil - ZR-1 Net Registry Forums

72ZR1 · 09-12-2008

i think 1990 is going throw to much oil.it has 87,000 mi. i used 3qt. this summer and only put 1,500 miles on.and smells bad out the exhaust.runs great.any thoughts would be helpful. thanks.

Polo-1 · 09-12-2008

90's do not have valve stem seals. They can be upgraded, and installed.

Kevin · 09-12-2008

the lt5 will use oil when run hard.

tomtom72 · 09-13-2008

Not trying to be a wise guy....so take this as a fwiw.

I figure you have run down the list of the usual leak source suspects? It's true that the 90's don't have exhaust valve stem oil seals and if you drive enthuiastically you will have some loss from there. I assume that by 'smells bad from the tail pipes', you mean burning oil smell?....not gas from bad spray patterns causing wash down & loading up?

Just in case....
Header bolts in the center of the manifold go thru oil galleys.
CCVBox cover gasket & hoses. This was my biggest leak, it was enough to run out of the valley tube & stain the oil pan. It looked like an oil spill in the valley! You can see in thru the passenger side plenum runners to the valley floor.
Oil pan bolts....even the ones up front.
Oil cooler lines.
Oil senders. 2 of them.
PCV valves need to be in good shape along with the plumbing.Much oil can be ingested thru this avenue if the PCV's are not 100%.

If most of the above have been gone over and nothing too dramatic was found; then I suggest compression & leak down tests maybe the next diagnostic to run. Maybe even throw a vac gauge on her and see if it bounces alot, usually that could be bad guides but not always...then do the leak & comp tests. That's all I can think to check....sorry I'm still learning too. Oh, forgot....what's the plugs telling you about what's going on in the chambers!

Tom

72ZR1 · 09-13-2008

thanks guys yes oil smell. no oil leaks.it burns oil when a don't drive it hard. I tryed just to see!

tomtom72 · 09-14-2008

Okay I'm lost.

You checked the plugs for signs of oil? The exhaust tips usually get fairly sooty, is it dry or wet? If there were a mechanical issue like rings or guides you would loose oil under load for sure and at light to moderate loads also....

Not to beat a dead horse.....you say you smell burnt oil, or burning oil...from where do you smell it? Standing at the exhaust tips you smell it? Or sitting in the driver's seat you smell it? Those exhaust bolts that leak will dump small amounts out on to the exhaust manifolds but usually it burns up before ever reaching the ground....so no tell tale spots in the parking space. If that motor used up 3 qts in 1500 miles.....something is amiss....I'm out of ideas, sorry.

72ZR1 · 09-15-2008

smell is at the exhaust.and the tips are black hope to pull all the plugs this week

72ZR1 · 09-16-2008

got the plugs out last night.7 of them like good but #4 plug had oil on it. tear down?

tomtom72 · 09-16-2008

Quote:

Originally Posted by 72ZR1

got the plugs out last night.7 of them like good but #4 plug had oil on it. tear down?

Okay, now we have something to work with. IMHO, if just one plug shows signs of oil in that chamber, I'd start with that cylinder and do a compression test and a leak down test. I would still put all the plugs back in and connect a vacuum gauge so I could see what the readings look like. Here is a link to reading and interperting vacuum gauge readings. http://www.secondchancegarage.com/public/186.cfm

I still can't see one cylinder eating that much oil by itself and the motor runs without a big miss due to an oil fouled plug....JMHO

Tom

flyin ryan · 09-16-2008

Quote:

Originally Posted by Polo-1

90's do not have valve stem seals.

on the exhaust valves.

09-12-2008	#1
72ZR1 Join Date: Jun 2007 Location: lasalle michigan Posts: 61	burning oil i think 1990 is going throw to much oil.it has 87,000 mi. i used 3qt. this summer and only put 1,500 miles on.and smells bad out the exhaust.runs great.any thoughts would be helpful. thanks.

09-12-2008	#2
Polo-1 Join Date: Sep 2005 Location: Washington Posts: 955	Re: burning oil 90's do not have valve stem seals. They can be upgraded, and installed.

09-12-2008	#3
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,632	Re: burning oil the lt5 will use oil when run hard. __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

09-13-2008	#5
72ZR1 Join Date: Jun 2007 Location: lasalle michigan Posts: 61	Re: burning oil thanks guys yes oil smell. no oil leaks.it burns oil when a don't drive it hard. I tryed just to see! Last edited by 72ZR1; 09-13-2008 at 04:03 PM.

09-14-2008	#6
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: burning oil Okay I'm lost. You checked the plugs for signs of oil? The exhaust tips usually get fairly sooty, is it dry or wet? If there were a mechanical issue like rings or guides you would loose oil under load for sure and at light to moderate loads also.... Not to beat a dead horse.....you say you smell burnt oil, or burning oil...from where do you smell it? Standing at the exhaust tips you smell it? Or sitting in the driver's seat you smell it? Those exhaust bolts that leak will dump small amounts out on to the exhaust manifolds but usually it burns up before ever reaching the ground....so no tell tale spots in the parking space. If that motor used up 3 qts in 1500 miles.....something is amiss....I'm out of ideas, sorry. __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

09-13-2008	#4
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: burning oil Not trying to be a wise guy....so take this as a fwiw. I figure you have run down the list of the usual leak source suspects? It's true that the 90's don't have exhaust valve stem oil seals and if you drive enthuiastically you will have some loss from there. I assume that by 'smells bad from the tail pipes', you mean burning oil smell?....not gas from bad spray patterns causing wash down & loading up? Just in case.... Header bolts in the center of the manifold go thru oil galleys. CCVBox cover gasket & hoses. This was my biggest leak, it was enough to run out of the valley tube & stain the oil pan. It looked like an oil spill in the valley! You can see in thru the passenger side plenum runners to the valley floor. Oil pan bolts....even the ones up front. Oil cooler lines. Oil senders. 2 of them. PCV valves need to be in good shape along with the plumbing.Much oil can be ingested thru this avenue if the PCV's are not 100%. If most of the above have been gone over and nothing too dramatic was found; then I suggest compression & leak down tests maybe the next diagnostic to run. Maybe even throw a vac gauge on her and see if it bounces alot, usually that could be bad guides but not always...then do the leak & comp tests. That's all I can think to check....sorry I'm still learning too. Oh, forgot....what's the plugs telling you about what's going on in the chambers! Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

09-15-2008	#7
72ZR1 Join Date: Jun 2007 Location: lasalle michigan Posts: 61	Re: burning oil smell is at the exhaust.and the tips are black hope to pull all the plugs this week

09-16-2008	#8
72ZR1 Join Date: Jun 2007 Location: lasalle michigan Posts: 61	Re: burning oil got the plugs out last night.7 of them like good but #4 plug had oil on it. tear down?