Oil consumption
- Thread starter Sequoia
- Start date
Yeah that's kind of high. That's about what I use for oil too but I'm still dealing with leaks.
How much do you have leaking on the ground?
How do your plugs look? If one cylinder is burning oil it may show up on the plug as a deposit.
This is from a P30 manual but still applies:
How much do you have leaking on the ground?
How do your plugs look? If one cylinder is burning oil it may show up on the plug as a deposit.
This is from a P30 manual but still applies:
It has been noted by long time owners over at GMCNet forum, that the top half to one quart of oil will burn off quickly in about 500 miles or so. The dipstick will then read just above ADD. If left at that level, it will stay there for another 1,500+ miles.
The general consensus is the higher level of oil in the pan gets whipped into a fog by the close clearances to the crankshaft. It then gets pulled through the PCV valve into the engine and burnt. Once the level drops a bit, this does not happen. Try letting the oil level drop a bit and monitor the consumption and see if it levels off.
The general consensus is the higher level of oil in the pan gets whipped into a fog by the close clearances to the crankshaft. It then gets pulled through the PCV valve into the engine and burnt. Once the level drops a bit, this does not happen. Try letting the oil level drop a bit and monitor the consumption and see if it levels off.
Or a dipstick that's not calibrated correctly. At my last oil change with 6 quarts added, the level still indicated below the 'add' mark. That was with 6 new quarts plus potentially 1 old quart in front of the hump in the pan, 7 quarts total (potentially) and it still reads low.
Sequoia,
As you have no sigfile, I am going to assume that is the model and that makes it a 455.
As said above, try running at the add mark before you do anything else. When Chaumière came to live with us, the lube oil consumption was 3~500. But then we were real close to home and a lube service so I let it ride and it strayed right there. And stayed that way until she broke a piston 50K later.
We don't know the coach mileage and if the engine has been changed, there is a decent chance that the valve gear covers were not replace the correct version. If it has not been overhauled, at least a valve job, then the valve guide seals are probably shot.
So, the first bets are that it is nothing serious. Drive her, enjoy what she can do for you and plan to work on the engine when you are ready.
Matt
As you have no sigfile, I am going to assume that is the model and that makes it a 455.
As said above, try running at the add mark before you do anything else. When Chaumière came to live with us, the lube oil consumption was 3~500. But then we were real close to home and a lube service so I let it ride and it strayed right there. And stayed that way until she broke a piston 50K later.
We don't know the coach mileage and if the engine has been changed, there is a decent chance that the valve gear covers were not replace the correct version. If it has not been overhauled, at least a valve job, then the valve guide seals are probably shot.
So, the first bets are that it is nothing serious. Drive her, enjoy what she can do for you and plan to work on the engine when you are ready.
Matt
Jumping in here rather than starting a new thread. Over the course of 1,400 miles I probably put in 15 quarts of oil, or pretty close. I do feel like it was going below 'ADD', and I kept adding more, at an unbelievable clip. So given what was said above, how low should I let it go? I assume when cold? I received a new calibrated dipstick while stopping in at Applied GMC, and they agreed that the former was even lower than it should have been.
Marcelo,
I think your engine does have a problem. That lube oil consumption is pretty close to what mine was when #7 piston was missing about a third of its rings.
Matt
I think your engine does have a problem. That lube oil consumption is pretty close to what mine was when #7 piston was missing about a third of its rings.
Matt
Matt, is this something that is serviceable typically or is this engine swap time?
Marcelo,
Do you KNOW how many miles are on this engine? Has it ever been apart? It may be time anyway.
It could be that the valve guide seals are shot and you got a set of the wrong valve covers. TZEs had special covers to reduce the lube oil carry over. Those could be serviced in place.
But the thing that should happen first is a cylinder leakage test. This is a better test than just cranking compression as it is very sensitive to the piston condition. If this says that there is a problem, you will know.
I knew in my case because I keep careful logs and when the lube oil consumption went from 2000+ per quart to 500 per quart+ I knew that something was wrong. She was only barely down on power.
Matt
Do you KNOW how many miles are on this engine? Has it ever been apart? It may be time anyway.
It could be that the valve guide seals are shot and you got a set of the wrong valve covers. TZEs had special covers to reduce the lube oil carry over. Those could be serviced in place.
But the thing that should happen first is a cylinder leakage test. This is a better test than just cranking compression as it is very sensitive to the piston condition. If this says that there is a problem, you will know.
I knew in my case because I keep careful logs and when the lube oil consumption went from 2000+ per quart to 500 per quart+ I knew that something was wrong. She was only barely down on power.
Matt
We do think that the engine has been apart at one point but have no idea when. We replaced the transmission just last month, so my brain is telling me we are due for an overhaul in general. I'd prefer to bite the bullet if we are talking engine swap, rather than jeopardize trips which are hard for me to make happen as is. Thank you for the insight, above. I will find someone here in the Portland area who knows these engines as step #1. What you are saying is resonating with me; we have good power, but the oil consumption is a bit ridiculous.
There is a little leaking below the middle center of the engine area from what I can see. I am not sure how to look at plugs or what I would be looking for.
If there's a problem with the engine burning oil, it should show up on the spark plug
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Hi there pdxbirchy...I am in Portland also and my 76 Eleganza has an oil burning and leaking problem as well. So far I have been unsuccessful in finding anyone in the Portland area who will even look at my coach...who did you find to work on yours? L. Miller
