amits001

I have a 1990 LS400. It has 177,000 miles on it. About a month ago the check engine light came on. I checked the oil level and it was a little lower than supposed to be. I filled it up. I got an oil change a few weeks ago. And the light comes on intermittently...Today I checked the oil level again and it was low. I'm not seeing any leaks anywhere....Where is the oil going? What is the problem and what can I do to fix it? Any ideas?

Thank you,

AS

Japanimal

For starters @177,000 miles your car isn't exactly a spring chicken so oil consumption is gonna be higher than an engine that has just been broken in. I'd check your rear main seal. You didn't mention how many miles you had driven on the oil when your check engine light first came on...so there's not much to tell you there. After you next oil change you should make sure you park your car on level ground that night....early the next morning go out and check the oil level before you drive it and see if it is still full. Each time a pistons travels inside an engine cylinder an extremely thin coat of oil is left on the cylinder wall and burned off. Sometimes you can drive 5,000 miles and the oil level will not budge...which is most likely to mean the moisture accumulation in your oil is about equal with what you are burning off. Also the oil type and weight will affect how much is burnt off. For instance an 850 mile road trip that I usually do in about 12hrs burns almost no oil when I am using Amsoil series 2000 Ow30, but makes a noticeable dent in the oil level whan running regular Amsoil Synthetic 5W30. If there is nothing visually wrong with your rear main and the day after an oil change the level is fine....I would do a used oil analysis. It's actually not a bad idea either way on an engine that has 177k on it. An analysis will give you a good idea of what kind of shape your bearings and other engine components are in.

Oh yeah don't just check the rear main check em all....I've seen quite a few higher mileage LS's with a leaky dipstick tube seal.

http://www.blackstone-labs.com/auto.html