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Q: Smoke that is not coming from exhaust when going above 60 mph.

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White smoke comes out the back of my car when I hit 60 mph or higher. I have a 327 sbc with a 3-speed turbo hydramatic transmission. I believe that the PCV valve has gone bad and is sending smoke out the back due to pressure since I just fixed my rear main seal but I'm not really sure if that's the issue. What are your thoughts? Thank you.

My car has 77000 miles.
My car has an automatic transmission.

Hey there. If the smoke is not coming from the exhaust, it may be possible that the white smoke is coming from oil leaking onto a hot exhaust manifold or another piece of the motor or exhaust. The PCV valve, as you know, helps to regulate the air flow to prevent oil being drawn out of the motor due to the vacuum that is otherwise caused during high RPM situations. This negative pressure is supposed to prevent oil leaks and oil from being burned by the motor. When this is not working properly, this may cause oil to be passed through or otherwise burned with the fuel in the combustion chamber or in some cases leaked out of the motor. To verify the problem, I recommend having a certified technician, like one from YourMechanic, diagnose the smoke issue in person so that the correct repair can be done.

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