Have a 2000 SS, I was startled when more than a year ago the oil light came on. The engine was dry!
A Houston dealer has done two 'pressure tests' on the engine over the past 12 months - nothing. The bottom of the car is clean, no leaks. There are small oil deposits in my exhaust pipes. Dealer insists that it is perfectly normal for a "high revving" engine like the LS-1 to use some oil in city driving. (I'm using 1+ quart every 800 miles or so!) Have 29,800 miles on car. Have always used Mobil-1 Full Synthetic and taken meticulous care. I read one article about rings flexing too much in this series of engines. Engine seal failure? Dealer acts like they do not want to fix it. Any hints? Thanks in advance for any advice. Much respect to the SS tech wizards!
[ 31. March 2003, 01:34 PM: Message edited by: Red-SS-Texas ]
Posted by OBSSD (Member # 1258) on :
For one, dope-slap your dealer because your car has an LS1, not an LT1. But seriously, I would say 1 quart every 800 miles should be enough to qualify as excessive, even by GM's standards. Do you often keep the revs above 3-4k when you're just cruising...high rev, low load use is a known cause of oil consumption in these engines. If so, try running in a lower RPM range for a while and compare. If it's still bad, you could try another dealer or contacting your regional GM rep.
[ 28. March 2003, 05:47 PM: Message edited by: OBSSD ]
Posted by 99Y2Y (Member # 1387) on :
I have read that light load high RPM's, ie;40MPH in 1'st gear is an oil burner particularly when cold, some cars have the ole "piston slap" problem, some do, some don't. The ones w/ piston slap obviously are going to probably have an oil consumption problem particularly when revved while not fully warmed up, you'll know if you have the piston slap gremlin if it knocks upon startup. That whole thing has been previously addressed in this chat room.
Posted by 2002Z4CSS (Member # 1393) on :
That is below the 1 quart per 1000 that GM says is normal. You may need to take the car to the dealer and see if there is any TSB's on the rings or pistons.
Posted by Bill Mason (Member # 1807) on :
If there are no oil leaks than oil can only be used up by burning in the engine. The fact that you have oil droplets on the exhaust tips supports that oil is being burned. BTW, IMHO oil on the exhaust tips is not normal.
Oil can get into the combustion chamger from either the rings or the valve seals. Here are some checks that may help track it down.
Have someone watch the exhaust when you first start the car after it has been sitting for a while (I would suggest for more than 1/2 hour). If there is blue smoke on start up then oil is leaking past the valve seals.
Next, have some one follow you to watch the exhaust while you are driving the car (or vice versa). If there is blue smoke when decelerating (using the engine as a brake) then oil is getting past the valve seals. If there is blue smoke when accelerating than oil is getting past the rings.
If you are concerned about the rings, I would suggest that you have a leak down test performed. This is different than a compression test, and should be able to be performed by any competent engine machine shop. It will show any cylinders where the rings are not sealing correctly and by how much.
The ring problem with LS-1s is that under light load at high RPM they flutter in the cylinder, letting oil pass by. The flutter is the result of ring shape and light tension in the rings. The "fix" is to tear the engine down and replace the top compression ring with a different design of ring. It is undercut and the contact point on the cylinder wall is pointed rather than flat.
The piston slap noise is "fixed" by replacing the pistons with ones that have less piston skirt to cylinder wall clearance. However, due to the reduced clearance the piston skirts must be coated to prevent scuffing of the piston skirt. The piston flutter can be avoided by driving at lower RPMs at light loads. The piston slap noise will not cause any problems. just deive with a light foot and lower RPM until the engine is fully warmed up (something that should be done all the time anyway) You must weigh this against having a dealer tear you engine apart and get it back together as well as the factory did (not going to happen IMHO).
One other thing that can cause oil consumption in the LS1 is oil being sucked in by the PCV system at sustained high RPM. This was "somewhat" fixed with the LS6 intake.
![[Roll Eyes]](rolleyes.gif)
But seriously, I would say 1 quart every 800 miles should be enough to qualify as excessive, even by GM's standards. Do you often keep the revs above 3-4k when you're just cruising...high rev, low load use is a known cause of oil consumption in these engines. If so, try running in a lower RPM range for a while and compare. If it's still bad, you could try another dealer or contacting your regional GM rep.