Just had the head gasket replaced on my 1998 Legacy GT and now has very loud clacking/rattling sound coming from the engine. I had the car towed to back to mechanic and now they claim they cannot get the car to repeat the same noise. Does anybody know what the noise could be?

 

Thanks in advance

There are several things it could be after fairly extensive work like that. Anything from a drive belt tensioner to something related to the engine removal. Go with the mechanic for a drive if possible and demonstrate the noise that concerns you.

Thank you for your advice. I have been back to the mechanic and still we are not able to make the clacking noise come back on command. Can a belt tensioner make that noise?

Yes it can. Sometimes they clack after a belt job and then straighten out. I would think your engine likely to have piston slap when cold that makes a rapping sound. That is considered normal if it goes away when warm.

This happens when the engine is warm or cold

I am sure you have some kind of warranty on the work. If it were mine I would drive it as much as possible to find any problems before the warranty ends.

If you have the noise again you might want to get a second opinion.

Thank you very much for all your help.

Actually it is much easier if the car is in front f you and not over the Internet.