2008 HHR 2.2L 150K
The engine sounds loud now. No check engine light. Just started a couple days ago. If driving own the road and I drop it into neutral and rev it up, the sound follows the RPMS. So this is not transmission or drive train related. Seems to be more noticeable inside the car. What could it be?

 

Could be the flex joint in the exhaust at the exhaust manifold. This is a VERY common problem on HHRs. Does it sound like its coming from the rear of the engine?

Steve

 

I’ll pop the hood tomorrow and do some thorough investigating. I have never replaced the chain or the water pump, hoping it is not one of those. Could be an alternator bearing, maybe. Can you see a rip in this flex pipe? I know it looks like woven stainless wire.

 

Check under the heat shield for a cracked exhaust manifold