BMW Forums : BimmerForums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hi All, great site, hope you can help.
I've got a 2003 E46 320D Auto estate with 52000 miles and it has developed an annoying knocking noise when started from cold which gradually goes when warmed up. You can hear the noise best at around 2500 rpm. The sound appeared to be coming from the P/S pump area so I decided to remove the main drive belt from the Pump to see if the noise went, which it did. However when I removed the belt I noticed the crank Pulley/Damper was split badley and had quite a lot of movement, and having search the internet it is aparent that this is a known problem. My question is, what are the chances that this pulley is the cause of the knocking noise, is it likely that the noise could be transmitting up the belt to the P/S pump because it does sound to be coming from that area. I know the pulley needs changing anyway but it just seemed a little odd.
Also I had to put it all together again as the Pulley nut is extremly tight. Is there a supplier of a special holding tool so that the bolt can be removed??

Any information would be apreciated.

Thank is advance :thumbsup
 

·
Legendary BFuk Member
Joined
·
12,959 Posts
This is a very likely cause and it is advisable to replace the part if damaged/worn even if it is not the problem

An engine will vibrate more at certain RPM's and the fact that you have a split damper would definitely be the first point in the process of elimination:thumbsup

Whilst the belt is off you also need to check that all the pulleys spin freely and there is no roughness:thumbsup
 

·
Registered
Joined
·
39 Posts
I'd defo start with the 'crank Pulley/Damper'. Its a process of elimination. Get that done first mate then go from there... Needs done anyway so its not like you'll be wasting money to eliminate that.
 

·
Registered
Joined
·
20 Posts
Can you let me know on here if this solves your problem. I also have the same problem on a 2002 320d. Knocking from cold, almost sounds like big ends in the olden days or a type of pinking sound but know its not that!! Hopefully its just the pulley/dampener you are talking about. Any other ideas from anybody on possible causes????
 

·
Registered
Joined
·
20 Posts
Incidentally if this is the cause (damper/pulley) of the knocking noise (and I really hope it is) why would it only knock when cold and not when warmed up??? This is why I thought the knocking noise was engine internal, thinking that noisey when cold but when warm and the oil was thinner and reached more parts that it stopped???
 

·
Registered
Joined
·
4 Posts
Discussion Starter #9
Just an update on the knocking noise. Pulley replaced yesterday and problem solved. From cold start no noises at any rev range.
I can't answer as to why it only occured from cold, the jury is still out on that one, but all theories welcome.
It also runs alot smoother as you would expect. :thumbsup:thumbsup
 

·
Registered
Joined
·
20 Posts
Can you just clarify which part you have changed?? I have had mine to pieces this morning and took the belt off but the noise seems to still be there!!! If its the part I think you are talking about (the damper type thing on the lower belt that tensions the belt???) then it doesn't seem too bad on mine, its got a tiny bit of play. Let me know?!! If anybody else has any theories on what could be the problem on my car let me know. It almost sounds as if its 'pinking' from cold sort of thing. Could it be the cam chain???
 

·
Registered
Joined
·
20,393 Posts
Can you just clarify which part you have changed?? I have had mine to pieces this morning and took the belt off but the noise seems to still be there!!! If its the part I think you are talking about (the damper type thing on the lower belt that tensions the belt???) then it doesn't seem too bad on mine, its got a tiny bit of play. Let me know?!! If anybody else has any theories on what could be the problem on my car let me know. It almost sounds as if its 'pinking' from cold sort of thing. Could it be the cam chain???
His was number 1 here http://www.realoem.com/bmw/showparts.do?model=AP72&mospid=47665&btnr=11_3313&hg=11&fg=18
 

·
Registered
Joined
·
20 Posts
Ah this might wel be where I am going wrong then.... I looked at the bottom belt and something that looked completely different. Is it the top belt I should be looking at??
 
1 - 15 of 15 Posts
Top