cobalt

I got my car back after having a 100cell cat installed and now I have this loud squeal almost like a bearing noise between 3 and just under 4k rpms. It is rather loud and i can't tell where it is coming from since I only hear it while I am driving. the car runs great I don't think i have a turbo failing but not sure. The HF K27 has about 4k miles on it.

Anyone experience this noise before. Someone suggested it is the bearings on my alternator but I don't think so.

X-1

The only bad noise I've had so far was after a month of rain driving, the serpentine belt idler started howling. I hit PP, the local indie and the stealership and NOBODY has this damn part in the PET!!! I ended up popping the bearing seals and repacking it. Now it makes "less" noise.
Turbo failures were very common on the Audi S4 K03s, and when they start to go they'd sound like a siren. K03 is a much smaller terb though. I think their most common failure cause was insufficient shaft/bearing cooling and too small shaft dia. Lots of forum pics of pre-cats with orphaned impellers, and a LOT of oil.

Boeing 717

Where did you get the Cat Anthony and where does it go????


JERRY

dholling13

Maybe a leak? I have this hissing noise coming from my engine compartment when I first start the car up and the motor is cold; but it goes away when I either rev the motor or when the motor warms up. Maybe record a clip and so we can hear it?

SonnyV

I had this squeaking noise when first start the car a while back. It turned out to be the fan belt sensor bearing. This one is pretty common. The fix is to buy a new assembly or just lube the bearing.

asimler

similar to Sonny I had a loud squealing but was from idle-2k and was just the fan belt slipping as it was worn. Could be worth checking the belt and tensioner/sensor thingy first - nice cheap easy fix.