Q: Intermittent loud hissing ( pressure relief?) sound and white smoke from pass side of engine

asked by on June 10, 2017

We recently replaced the A/C condenser motor (the previous one was making an intermittent loud grinding sound) and upon restarting the car afterwards, when the engine was warm and the a/c was off, we heard a loud hissing noise (sounded like a pressure relief valve) and smoke started coming out of the passenger side of the engine bay. Once the hissing sound subsides (each time it varies between 2-10 seconds) the white smoke stops.

My car has 204000 miles.
My car has an automatic transmission.

Hi there. It is quite possible that your radiator cap is damaged or you have a loose AC connection line that is not properly tightened. It would be a good idea to have a professional mechanic complete a smoke coming from engine inspection to determine what is causing this issue as it could indicate a potentially major issue.

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