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Q: what could cause my mercedes 560sec to smoke when it warms up but not all the time

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smokes once an awhile while warming up,smokes bad,and then sometimes its good,runs and idles great.

My car has 155000 miles.
My car has an automatic transmission.

A very common failure on your engine when it gets old is the valve stem seals. These little synthetic seals are under the valve springs and are there to prevent the lubricating oil from running down the valve stems into the engine. When the seals are tired, the oil can run into the ports and sit there until the engine starts up, causing a lot of bluish white smoke for a short time. Replacing the stem seals on a Mercedes V8 is a big job so you want to make sure that is what’s wrong before you make the commitment. Your best bet is to contact Your Mechanic to have a technician come to your home or office to diagnose your smoking engine and let you know what really needs to be done.

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