Losing engine oil

MOHAMED HUSSIEN

MEMBER
2001 LEXUS LS 430
4.3L
V8
2WD
AUTOMATIC
145,000 MILES

Hi there. I have the car listed above which is driving me crazy by slowly losing oil. It loses around 1 quart per month. I think I've replaced every seal that could've been replaced or anyone could think of.
the rear crankshaft seal(which involved the removal of the transmission) - replaced.
valve cover gasket - replaced.
PCV valve - replaced.
engine oil pan gasket - replaced.
maybe engine is burning oil? No smoke is coming out of my exhaust, even with the highest RPM revs.
maybe head gasket is blown? Engine oil and coolant both looks super clean.
I really love this car and don't want to sell it. But this continuous oil decrement is driving me crazy.

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

It could be burning the oil. When it burns oil slowly as in your situation, the catalytic converter can absorb the oil and it will not produce any smoke.

https://www.2carpros.com/articles/blue-smoke-from-engines-exhaust

I would do a wet and dry compression test to determine if the rings are the issue.

https://www.2carpros.com/articles/how-to-test-engine-compression

Normal oil consumption is 1 quart every 800 miles.

Roy

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