Simbamoe

Engine making a weird noise a partial throttle and low rpm but when supercharger is engaged it’s gone

N_Rob

I’m currently hunting this same noise on my 04, I found that the bearing in my supercharger pulley was bad so I’m changing that out next week, next step is to remove both the belts and spin everything by hand. Please update this thread if you find what it is, I’ll let you know if I find anything.

Simbamoe

I am changing out the supercharger belt on weekend hoping to fix the noise. i was always guessing the bearing for the supercharger could be the problem too. I asked a lot of e55 owners on ig and they all give my different cause it could. I'm always gonna check over what they told me it could be.

Simbamoe

so i changed the supercharger belt last friday and the sound reduced but i can still hear from time to time. when i hand spun the supercharger pulley the bearing sounded bad so i suspect it is the bearing.

N_Rob

Interesting. I changed my supercharger pulley bearing just a few hours ago and my noise is still there, although roughly 70% quieter. Let me know how changing the bearing affects yours. I’m going to get to the bottom of this LOL

Simbamoe

Damn if it is not the bearing. im going to check out the suspension. just wondering how long have u been hearing this noise and when did it start and how many miles on your e. i have 100055

N_Rob

I doubt it’s the suspension to be honest, but wouldn’t hurt to check. My car has 187k miles I’ve been hearing it for roughly 500 miles. I’m almost positive my sound is belt driven or maybe transmission. Mine started about 3 months ago (I don’t put many miles on my car).

Simbamoe

taking the e to a shop on saturday to get them to diagnose the noise have not been able to figure it out myself

Agent-A01

Try putting the car in 3rd gear and driving up to 80.
Slowly coast down in speed and see if the noise gets worse.

To me it sounds more like it's coming from the transmission.

N_Rob

Definitely update this thread with what they tell you. I have a sinking suspicion it's transmission related like the guy above said, like tq converter whine or front trans pump. If it's front trans pump that's a big RIP as I understand it. New trans needed to fix that I think.

EDIT: Might also be worthwhile to either have the shop check the diff or do it yourself. I'm unfortunately away from my car for another 2 weeks or so, so I will be making no headway (not that I was getting anywhere before, I got really busy lol).

Simbamoe

Wouldn’t the car have blown or over heated by now if it was the trans pump??

N_Rob

Not necessarily. The sound could be a failing pump, not a failed one. If we’re lucky it might just be a clogged trans filter or low on fluid if it’s trans related at all. Out of curiosity, when was the last time you had a trans fluid and filter change? The previous owner of my car said it was done 20k miles before I bought the car but I looked through the service records he gave me the other day, it only noted a check on the fluid 20k miles before I bought it. I’m starting to think it’s been quite a while since my trans had a fluid/filter change, so I’m going to start there. It’s cheap anyway.

Simbamoe

Oh ok gotchu yeah I don’t know when it was done for this car I’m have to check

N_Rob

Just coming back to update this thread in case anyone has the same noise in the future. I did a full transmission service and my noise went away (filter, fluid, pan gasket, and 13 pin connector). I bought the 722.6 service kit on FCP Euro and added on the 13 pin connector just as preventative maintenance. Before doing anything, I checked the transmission fluid level with the 722.6 dipstick (got mine on amazon: ) and I was significantly low on fluid. I believe this was the cause of the noise because my filter didn't look especially clogged but it's hard to say. Plenty of DIY's about this service, took me about an hour working on my back. Hope this helps and remember that the car must be running in order to get an accurate measurement with the dipstick.