Random occurrences; when starting the car hot or cold I here a knock sound on the engine bay. Sometimes it is more like a engine mount hitting the fire wall ( mount checked a okay). Sometimes it more like a miss-fire knock.

Any one experience this? What was the reason and solution if available

thanks

 

I hear weird noises, usually soon after starting...i have narrowed it down to parts expanding/contracting due to the heater or ac...but mine felt more behind the dash then under the hood.

 

Had the A/C on? I am always annoyed by the loud knock A/C makes when you turn in on.

 

+1, or the fan it sounds like the compressor is gonna sling thru the hood.