Help with engine noise

BADRAT · 07-01-2011, 11:39 AM

hey guys! ive come across a bit of engine noise with my 2000 323i. especially after a bit of driving, the noise seems to be more noticeable. ive changed my oil, rebuilt the vanos as well as changed belts and checked ac/waterpump/tensioner/etc bearings. any idea what this may be and how serious of a problem im looking at. ive managed to find a video on youtube with the same sound and description. take a look here

http://www.youtube.com/watch?v=_a1fhZAZwpM

thanks, i appreciate any help you may provide

Ceeker · 07-01-2011, 02:31 PM

are you absolutely sure your timing is "bang on?" also check the pollution air pump. It sounds like it is coming from there as per the video.

Eurostyle · 07-02-2011, 01:47 AM

Quote:

Originally Posted by Ceeker

are you absolutely sure your timing is "bang on?" also check the pollution air pump. It sounds like it is coming from there as per the video.

The air pump only comes on for short time at cold start up...No way near "especially after a bit of driving" like in his case...Not even mentioning the pump makes a loud sharp (sucking/compressor) noise, not ticking/knocking!

Ceeker · 07-02-2011, 07:40 AM

Quote:

Originally Posted by Eurostyle

The air pump only comes on for short time at cold start up...No way near "especially after a bit of driving" like in his case...Not even mentioning the pump makes a loud sharp (sucking/compressor) noise, not ticking/knocking!

one can never tell; I've heard stranger things under an engine bay. the air pump is suppose to come on for a short time..but who really knows..it's obvious hes going to need a stethoscope to narrow down the potential area - needs investigating and shouldn't omit any possibility. process of elimination!!

new member · 07-04-2011, 12:25 AM

The sound in the video is coming from the loose heatshields on the top of your exhaust manifolds. VERY VERY common problem with E46s.

Easy fix, get your pliers and rip them off. Its a 2 piece design , all you;re diong is ripping the top part off.

Other noises that i heard were off of a shot water pump bearing and a bad DISA, but those noises could\ve been deceived by the noise of teh loose heatshield.

I can bet $1000 thats its teh heatshield in that video, what you have I have no clue because I'd need a vid of your car to tell.

BTW, aip pump never sounds like that, its loud at times but it never rattles. Yes, it works only at cold starts.

BADRAT · 07-06-2011, 11:48 AM

i can rule out the water pump bearing and DISA, they were both recently looked at. in terms of the timing, how would i check that? any good diy's available?

new member · 07-06-2011, 08:30 PM

stick your hand by the exhaust manifolds and see if the heat shields that are between the head and the manifold are loose.

If you have IDENTICAL sound to that in the video then I can bet $1000 that its the shieds.

BADRAT · 07-08-2011, 02:57 PM

okay great, ill take a look at that and let you all know the outcome.

alberto · 07-13-2011, 02:31 PM

hi guys!
i have the same noise and i didn't solved yet.
in my case not is the heatshield of the exhaust manifold.
this is a video of my car: http://www.youtube.com/watch?v=5bjmUAsDY9c
BADRAT, can you post a video of your noise?
have you found the solution?
thanks

alberto · 07-13-2011, 06:46 PM

pd: in my video, i say the knocking noise, not the whining of the alternator. BTW, which part of alternator makes this whining? how i can solve it?
thanks

new member · 07-13-2011, 10:59 PM

Alberto, scan the car. It could be a faulty O2 sensor or a faulty ignition coil, causing a misfire. The video sounds like a misfire a bit , could be an exhaust leak but very unlikely.

SCAN your car and go from there tehre might be some stored codes.

BTW, teh sound in your video is NOTHING like the one of OP. Two completely different sounds/noises.

alberto · 07-14-2011, 12:30 PM

Quote:

Originally Posted by new member

Alberto, scan the car. It could be a faulty O2 sensor or a faulty ignition coil, causing a misfire. The video sounds like a misfire a bit , could be an exhaust leak but very unlikely.

SCAN your car and go from there tehre might be some stored codes.

BTW, teh sound in your video is NOTHING like the one of OP. Two completely different sounds/noises.

i scaned the car few days ago and the only engine code that i got was a thermostat failure (bad electronic control of thermostat that causes 10ºC higher engine temp than normal).
this rattle can be caused by old spark plugs? loose post-cat sensor? (pre-cat are tight). bad exhaust valve timing? (bad vanos seals) or what?
i will check all this things and ignition coils.
i think that the background noise (knocking like "tac-tac-tac") is the same in both videos.

and what can you say me about alternator whining? it's a really loud noise that kill the L6 sound of this car

thank you

alberto · 07-14-2011, 01:11 PM

other video of my 330ci: http://www.youtube.com/watch?v=YHFu3VSaBgc

BADRAT · 07-21-2011, 11:49 AM

hey, so the noise on my car pretty much vanished. the only thing thats a bit loud is the air pump, but that's a different sound that I'm not worried about. the heat shields were not rattling.

alberto · 09-23-2011, 08:52 PM

any update?