well, that eliminates a lot of possibilities.


i was trying to chase a noise also. i took my belt off and spun my water pump and was sure it was causing the noise. a bmw tech buddy also listened to my pump with a stethoscope and was sure it was bad. i replaced it, but the noise was still there. replaced the idler pullies, noise still there. then i finally figured out that the noise was coming from the belt tensioner pivot.....it was dry and lost its lube with age. and was making a loud noise as it vibrated from the belt running on it.

 

Thanks for the advice Turbo. I might have that problem too. Anyway, do you happen to know what I can do to clear the engine service soon light? Removed the serpentine belt, ran the engine for like 10 to 15 seconds to find out if it is from the pulley, got the dynamic active steering warning. After reinstalling the belt, the warnings are gone but engine service light is on now.

Also even though after installing the new tensioner pulley, it's still loud, a dry rattling noise like so either my water pump is on its way out; well either that or need to consider about the timing chain tensioner.

 

so you replaced the whole tensioner, and not just the pulley?

when you started the car with the belt off, was the noise gone?

as for the check engine light, it may go away on its own. if not after a couple of drives, then you need to get the code cleared.

 

I replaced the entire tensioner pulley unit. It was bad anyway, I can hear the dry bearing when I spin it by hand.

When the belt was off, the engine was still loud, at least louder than couple months ago so I'm assuming it's something else internally, such as the timing chain being loose but it only has 70K miles so it shouldn't happen.

Appreciate any suggestion you or anyone can give me here before Monday when I bring it to a local indy to have it diagnosed.

Richard

 

exactly what does a bad water pump sound like? I spun my it didn't rotate freely, had some resistance but did spin and does make a litle noise. I'm assuming it's on its way out too then.

 

well, mine wasnt bad necessarily, but it did have 85k miles on it at the time. it didnt spin freely, and could feel the bearings being a bit rough. i didnt mind just changing it out anyways, just for peace of mind.


if the noise was still there with the belt off, then it may be internal....like a broken timing chain tensioner, but you mentioned that the noise doesnt change if you rev the engine??

 

at idling it sounds like coming from up front and rattling noise inside the engine itself, when I rev it up, the rattling gets bit louder so it blocks out the noise from up front. May be I have no choice but to bring it in which I hate the most. Always prefer DIY instead of having to bring it in

 

here is what my water pump sounds like with the belt off, it seems to be making noises when I tried to spin it by hand. Please give me you opinion on it since you replaced yours before.

 

Next thing I would check is the vacuum pump. It is on the left side of the engine.
It is very common to fail on N62 engines
http://realoem.com/bmw/showparts.do?...78&hg=11&fg=45

GL

 

Thanks DW...I think I narrow it down to the water pump pulley. Still need to to determine if I need to replace the entire unit though. Just need to find out if it's something else I need before I go ahead and order the parts. Hate having to wait for the parts to arrive at different time. Will definitely look at the vacuum pump once I'm able to get my hand on a stethoscope. Local Autozone doesn't carry in store.