I have 54k miles on the car. The engine has had a tapping noise for almost year but seems to be slowly getting louder. My mechanic said it is not coming from the valves but from the middle rear of the engine, and he doesn’t know what it is. He also said that it could be very costly to repair.
What could it be and should I worry?
Time to skip the mechanic and visit your Subaru dealer. If you live in the United States you have a 5 yr/60,000 miles power train warranty which covers this type of thing.
As was already implied, I really can’t fathom why someone would be going to the local garage for an engine problem like this while the warranty is still in effect. Especially when the mechanic admits that he has no clue!
Hopefully, the OP has complied with the manufacturer’s maintenance requirements and has kept the receipts so that he/she can avail themselves of the warranty coverage that they paid for.
I also have a 2003 Subaru Legacy with less than 50,000 miles that has a tapping noise in one piston (rear, driver’s side), especially loud when the engine is cold. The tapping never goes away – just gets quieter. Dealer says it is a piston slap and “normal” and calls it the Subaru “purr.” I’ve read postings online of engine failure – of course after 60,000 miles. Any way to get rid of the noise?