Hi! I'm new to the E60 board but not to BMW. Posted a hello in the new to the forum, forum.

So, I just picked up my new to me '04 545i that I test drove extensively but never noticed this slight rattle. It occurs when coming to a stop around 600 rpm's and again on accelerating through the 600 rpm band. At first I thought it might have been the Vanos / valvetronic trying to retard back down to idle. It's a really slight rattle and only happens as the rpm's pass about 600rpm. It seems to be coming more from the passenger side toward the front of the engine. I've searched around and found quite a bit on the rattle. It seems like there are quite a few of you that have narrowed down your rattles to the a/c compressor. I just took it out and engaged the a/c and it doesn't seem to do it when a/c is on. I know the compressor in my e36 was a little noisy but the one in the e38 doesn't make a peep. Seems like this could be the source.

It's such a small little noise maybe it's just me over-reacting. Has this happened to anyone else? If so, what did you do to fix the issue? New compressor?

Thanks in advance!

 

depends the sound if you could sound clip it please 545 engines are known to be kind of rough on idles

 

I have the exact same rattle @ 600 rpm. I really cannot pinpoint the cause, but it does sound like it's coming from the vanos area. I've noticed that it's even heard while parked and I start to turn the steering wheel. I wonder if it has to do with the power steering. Any suggestions?

 

If you turn off the a/c do the rpms go down to 500? I have I believe the same issue, 550i though. It sounds like a not oiled chain... really annoying. I don't know if you are speaking about the same thing. I am at the dealer on Monday so I'll see if the computer can find out something..

 

My rpm's stay pretty consistent at 500rpm at idle with or without a/c. I think you hit the sound exactly with the not oiled chain. Almost a slight Isuzu diesel sound. It's only as the rpm pass through 600 though. Weird, it runs like a top beside that noise. Keep us informed of what your SA tells you. My tech friend is working on my wife's 7 on Wednesday so I'm going to stop by at the same time and see what he says. My wife tells me I'm crazy and to turn up the radio!

 

Hi,

Did any of you guys figure out what the issue was here?
I have the exact same issue where it only has the rattling sound as it passes through 600 rpm while increasing or decreasing rpm. It doesn't occur while A/C is on, because the idle rpm jumps to ~750 rpm when A/C is on and is past the range where the rattling occurs. However, with A/C off, it idles at 500rpm and has to pass through the rattling at 600 rpm. I've got a 2004 545i. I had this checked out at a BMW specialist garage and they tell me it's coming from the VANOS. Apparently, there is a VANOS software update specific to my car, but the mechanic isn't 100% sure that would fix the noise.
Hope the original poster or any others with similar problem figured it out and posts an answer here.

Thanks,
puzzled.

 

Good luck guys, im in the process of trying to work out what my slight engine rattle is as well

 

Ben's 545i, did you ever figure it out?????

 

Any luck in sorting out the rattle noise?

 

I just had the ac compressor replaced last week on my 545. It was making a bearing noise. They first replaced the water pump and pulley. You better hope it is not the ac compressor. The price from the dealer was about 2k. The adviser told me the compressor runs all the time even with the ac off? Good luck if it is the ac compressor it won't be cheap. Thank god a had an extended warranty. My bill would have been $3400.00