So, I've noticed within the past month that if I leave my car overnight or for several hours it makes this loud grinding noise or maybe sounds like a pulley bearing. However, the noise goes away once the engine is warmed up or within a minute or two.

Things I've done or eliminated.
I changed my oil today and the noise was still there. Although, my AT seems to burn a lot of oil between changes.

Changed my timing chain tensioner, water pump, primary chain, and guide rails about 7/8 months ago. So, I don't think it's the chain rattle, but I could always pull of that access panel to verify it.

Deleted that extra pulley.

I changed the belts in that same timeframe as well, but I used to have a belt squeak on startup. So, I might replace the belts again, but I'm perplexed it sounds like a bearing, but it goes away.

No performance problems or CEL at all.

 

http://www.harborfreight.com/mechani...ope-69913.html

 

Same problem have no idea

 

I have one of those and the noise doesn't last long enough to track it down. It did sound like it comes from near the passenger side valve cover.

 

How long have you been having this issue? Any problems popup?

 

Are you refering to the grinding noise that last 3 to 5 seconds?
Gary

 

It's a grinding noise, but extremely loud and just started this past month. It goes away when the engine is warmed up. Only happens overnight or sitting for a few hours. Sounds kind of like a bad pulley bearing.

 

I'm having th same issue with my 03 6MT. It only lasts for about 2-5 seconds and then stops. No performance breaks or anything.

 

After lettin my car sit for a couple hours then car starts let the carm warm up and as I start to give it gas it last like 2 seconds and it sounds like grinding in the engine had it sounds like that for 5 months no performance issues or check engine lights so until then I don't mind it