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93 Sc400 Smokes When I Start It


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When I start my car in the morning or if sits for a while smokes . White smokes comes out of both tail pipes for about 20 seconds then its fine. It doesn't smoke when I drive. Does anybody know what I should do for the problem?

Thanks,

Ray

This symptom is a common indicator of worn valve guides and/or valve stem seals - this isn't a Lexus diagnostic; it's a symtom of valve seal leakage in virtually any overhead valve automobile engine. When the engine is shut down, worn valve guides and valve stem seals can allow small quantities of motor oil to "follow" the valve stem right down past the seals (this is what the valve stem seal is there for - to prevent this leakage) and valve guides into the combustion chambers. When the engine is started again, the oil that has accumulated on the valves and entered the combustion chambers will be burned off causing the pale blue oil smoke you are seeing. The smoking stops as soon as this oil burns off, and the reason it doesn't happen again while the engine is running is simply due to combustion pressures blowing up past the valve guides and stem seals in the opposite direction. There is usually some increased crankcase pressure as a side effect of these gases being able to get past the guides and up into the valve covers and thus on to the crankcase. The fix is a valve job by a professional who can replace both the valve guides and seals.

If it doesn't smoke under hard acceleration, it probably isn't piston rings.

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I am going to add my two cents and disagree with Tomj8.

I don't think you are burning oil.

I think it is coolant or fuel.

Oil typically has a blue tint to it and you specifically mentioned it was white.

Does your car idle rough during this time and then smooth out?

If it is coolant (you can smell its sweetness in the exhaust smoke) you may be looking at a head gasket job.

If you smell excess fuel in the exhaust, it may just be running really rich for some reason at startup. Possibly a leaky injector or something.

My money would be on coolant leakage.

Tom

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