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My friend’s 2000 Toyota Corolla is losing oil but there isn’t any apparent blue smoke while driving.
Opening oil cap there is noticeable sludge on the underside of the cap and on the valves.
My question, does sludge build up cause a loss of oil? I’ve read it might be a valve guide seal issue causing loss of oil. Are the two related at all? Would that cause sludge or vice versa? Thanks
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Basically the same oil neglect that caused excessive sludge also likely caused premature piston ring and valve guides/seals. Some engines just tend to sludge no matter what (Hyundai/Kia, VW/Audi) but for most others, it takes oil neglect that will actually hurt things to make a lot of sludge.
Check this out:
[quote=”Fopeano” post=116811]Basically the same oil neglect that caused excessive sludge also likely caused premature piston ring and valve guides/seals. l actually hurt things to make a lot of sludge. [/quote]
Curious how seals can go bad from neglect of oil changes? Is it they dry up?
Behind the oil control rings are holes that return the scraped off oil to the crankcase. These holes can plug with sludge and when that occurs, oil consumption will increase.
[quote=”barneyb” post=117864]Behind the oil control rings are holes that return the scraped off oil to the crankcase. These holes can plug with sludge and when that occurs, oil consumption will increase.[/quote]
So you’re saying if the oil can’t return to the crankcase it will cause it to burn off?Yes. But understand a certain amount of oil will always get past the oil control rings. Even a new engine burns some oil.
[quote=”barneyb” post=117884]Yes. But understand a certain amount of oil will always get past the oil control rings. Even a new engine burns some oil.[/quote]
Interesting. I’ve asked numerous people if sludge can consume oil and they all sad no it would be a separate issue.If you look down a ways in ToyotaKarl’s RAV4 Adventure (with engine rebuild) in Repair Central you will see where he is cleaning the piston oil return holes with a drill bit.
So with my friend’s Corolla that has engine sludge. She needs to add oil about every two weeks and it’s almost always at the first dot on the dipstick by then.
This is from the sludge blocking the oil from returning to the crankcase?
Disappearing oil can be due to several other things – leaks, worn valve seals or valve guides, worn cylinders or pistons/piston rings. Excess blowby can push oil into the intake manifold and make the above problems worse. You need to take into account the condition of the entire engine.
[quote=”myfavecoupe_” post=117861]Curious how seals can go bad from neglect of oil changes? Is it they dry up?[/quote]
What goes on is that when the oil gets really old, a lot of bad things happen to it. To cut to the chase, it gets dirty enough to get abrasive and physically sand away at seals and sealing surfaces. When oil gets dirty enough to do that, it also tends to sludge up as well. If you want a better explaination of what happens, just say so and I’ll explain further.
It’s tough to get a good answer to the question “does sludge consume oil?” because technically that question doesn’t make sense. How it’s phrased is really important to understanding what’s going on. It’s more that the sludge and oil consumption CAN be caused by the same problem, but they can also happen one without the other OR they can both be happening at the same time for different reasons.
[quote=”myfavecoupe_” post=117902]Just so I’m not confused, sludge can cause oil to disappear as well right?[/quote]
The sludge is a effect/result of a condition, not a cause.
Sludge alone will not cause oil consumption unless it has plugged the oil drain holes in the cylinder head(s).More oil on top of the head around the valves can cause oil usage because the valve seals are not designed to control the extra oil.
The neglect that caused the sludge has probably worn the engine piston rings, cylinder walls and valve guides prematurely as well as gumming up the rings and pistons that can cause oil burning.
Sludge is caused by extended oil and filter changes, incorrect or poor quality oil, short trip driving especially in cold weather, a plugged crankcase ventilation system and sometimes just poor engineering
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