Rattling engine noise
 

Well guys I'm still trying to track down this rattle noise from the front of the engine bay. It's only noticeable if you stand in front of the car or have the hood up; you cannot hear it from inside the car at all. I've just replaced all the pulleys w/ a new serpentine belt. Car has a brand new fan clutch and just had an oil change at the BMW dealership in town. At first I thought it was the VANOS unit but from what I've read it only happens at 2k-3k RPM's. I also had a friend check the water pump with a stethoscope and he said it sounded fine. So I'm at a loss at the moment. Hopefully somebody will be able to pinpoint the issue.

Edit: I also forgot to mention that I unplugged the DISA valve and it had no change on the noise.

http://www.youtube.com/watch?v=lEJc-...&feature=g-upl

Did you rule out the DISA valve?

I unplugged the DISA valve and it didn't make any difference in the noise... still was present.

Well I know one issue that could be causing this. When my buddy re-installed the fan and the housing he didn't clip it in at the bottom so I think the fan might be hitting the shroud. I'll know more tomorrow when we take it back off for re-installation.

One of the guys on another BMW forum is saying something about the timing chain guide being a possibility? God I hope not.

Anybody?

Water pump or tensioner pulley or even idler pulley. Check those.

Tensioner and idler pulley are brand new. Thinking it might be the water pump & pulley... the fan has a little bit of play in it. Not a lot, but there is some there for sure.

The chain guide would be a very rare item....

Curious to what this problem is. I have something similar

When I read that, I was pretty scared about that being the issue. But when I starting doing some research on the internet and I couldn't find once single case of that being a problem. Even on neglected cars it wasn't something that was an issue. The mechanic I spoke to said it sounds like a VANOS issue, but I'm just not sure that's it either. The car runs great and the motor pulls strong... I just hate that damn noise.

I'm really beginning to think this is a water pump/pulley issue. The noise is still present until you rev the car to about 2.5K-3k RPM's and then at that point the engine just gets loud enough to where you can't hear it. The fan clutch is new and you can move it around, but just barely. I'm going to take the fan and belt back off today and I'm going to check the water pump while i'm there. It was done at 85k miles and I just hit 148k so it needs to be done anyway. I was going to wait until Christmastime but I'll go ahead and get it out the way.

First, you have a known issue with fan/shroud, so take care of that and see what you get.

You can also use a hose as stethoscope and listen yourself. I use a 5' section of 1" d flexible electrical conduit from HD and it works great...just be careful around moving things.

Also, check your belt from the side to see that it's square across all the pulleys.

If the wp is wobbling, it could be internal to the wp, or it could be motor mounts.

If you do replace wp, I'd suggest you consider doing more with your cooling system if you haven't done anything else on it...therm, hoses, ET... I like low-hanging fruit...which is why I'll leave it to Mango's sticky thread to 'pitch' cooling system work to you! LOL

Fixed the fan shroud and that didn't solve the noise. The water pump was replaced 63k miles ago so it's time. I was going to wait until Christmastime and get it done but I don't want to risk damaging the engine and will go ahead and order it with a new thermostat and hoses. The side tank has a date of 10/11/11 on it so it not even a year old yet so I will leave it alone. I'm going to take the belt back off and mess around with the water pump/pulley and see if its noisy. Betting it is. Well, maybe more like praying.

im having a somewhat similar rattle from my 2000 323i. i have a thread going if i find out what the problem was I will let you know.

Yes please do let me know what you find. I'm extremely curious to solve this issue. I am going to take it by a mechanic tomorrow and ask them what they think it could be. Still going to order the water pump and thermostat tonight as its time for that to be replaced anyways.

Your a good man Dmax! I wasn't able to take the fan back off today (spent all day doing a tune-up) but I will sometime this week get it back off and check it out to see what's going on. Thinking about taking the car by a BMW mechanic tomorrow and letting him listen to the noise and see what he thinks it could be. The noise is most obvious when listening through the kidneys so I really think it's something water pump/fan clutch related though I just replaced the latter back in June. Is there a possibility that its bad? There seems to be a lot more fan movement than there should be and the fan almost looks unbalanced at times.

Try this - grab your expansion tank cap, and try to push it back and forth (towards the engine and away from it). See if it moves. If it does, there are some rubber mounts for the radiator that hold it in place! And they may be shot. I am pretty sure item #12 in the diagram below is a screw type mount, that can be raised and lowered to secure everything in place. This may be the source of some of the noise.

http://realoem.com/bmw/showparts.do?...45&hg=17&fg=05

Hmmm never thought of that being a possibility but it certainly could be something to look at. I'll check it out in the morning. Thanks!

Sounds familiar. I'd say water pump. Remove the belts and spin the pulley, you should feel it if something is wrong. You mentioned a slight play at the fan. Chances are that pump needs replacement.

You also mentioned 63k miles. You've gotten your money's worth. My last Graf only made it to 40k before it started making those noises.