ras545i

Hi all,

I just wanted to return to update the thread. So I had my mechanic replace the a/c compressor which was covered under my extended warranty. He also went ahead and changed the water pumps, belts, and repair my coolant pipe(sits above the engine). The pipe was causing coolant leakage and puddles when parked.

The car runs puurrrfect now...no rattling/loose chain sounds to drive me crazy at the light......
Hope this could be your issues also.

04 545i Sport Pkg.

Brendan412

You should be able to cut the belt and run the A/C fine. Don't quote me on that but do a search for it. I know I've read about some guys cutting/removing the belt and the noise going away. I'd first try running the A/C to see if the noise goes away. Also check the exhaust bracket that is right behind the transmission. Its a rod mount with two bolts (one on each side), and the nuts tend to come loose and could transmit an exhaust rattle up the the engine. I checked mine hoping that this would be the issue but it is not. I'm pretty convinced that the noise is from the A/C compressor itself. Will be doing a replacement within the next few months and will post results upon completion.

160THSOAR

Just to follow up on my last post, I believe the rattling sound I was hearing were the bearings in my water pump, it blew on me while driving on the freeway. Thankfully I wasn't on any curvy roads, because I completely lost power steering, and had a hell of a time getting the car off the freeway and into the parking lot at work. After replacing my water pump, the rattling sound was gone, and has been for about 300 miles.

southgate

I have a M54, saw the AC compressor pulley/ clutch moving in and out of belt alignment, Mine is a Loud rattle when idle, but once I was on the road it seemed to calm down. AC is fine. Going to tear it down this weekend...and see what I come up with.