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Q: Smoking/steam from back of engine.

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I replaced thr head gasket and water pump and timing chain and tensioners. i was trying to rebuild engine and when i put it all back together it starting smoking out of the back of engine about 2 minutes after i started it. so i thought the gasket dident seal so i bought a felpro head gasket instead of the cheap one and it did the same thing when i started it. i need help figuring out where the smoke is coming from.

My car has 180000 miles.
My car has an automatic transmission.

A: When you install new parts, there could be ...

When you install new parts, there could be some initial smoke or unusual vapors as factory coatings burn off, so the first thing you want to do is make sure that this is not a transient issue or false alarm. For example, if in working on the car, you dropped oil or grease on the manifold, it WILL smoke a lot when you first start it up.

Head gaskets require a really precise protocol and you have to check the head and block for flatness with a machinist’s straight edge before you even consider installing a new gasket. If the surfaces are not flat within .002 inches (typical spec; check your FSM), you are wasting your time installing a new gasket because it will leak. The surfaces also have to be smooth as a mirror, you have to use new head bolts, and the torque value and angle have to be set precisely in the specified sequence. If you did all this, you probably do not have an external oil leak from that segment of the engine.

Check the obvious stuff like leaking valve cover gasket, cam seals, distributor o-ring and so forth. Also, try to see if you can actually see a leak. If the leak has the odor of antifreeze, obviously you will want to check the cooling system for leaks. If you’re unable to pinpoint the issue, have a certified technician, like one from YourMechanic, diagnose the smoke firsthand for an accurate repair. Best of luck.

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