E55 whining/howling noise
01-31-2019, 10:22 PM
#1
Member
Thread Starter
E55 whining/howling noise
Hey guys, my car has been plagued with issues lately. Nothing major but you know how it goes. This though, I'm slightly worried about. I know the famous E55 startup whine that they all have, this is different. Mine starts up (with the normal whine that goes away after a few seconds) and sounds normal until it has warmed up. After that it develops a constant, well, howl essentially. The howl is most noticeable at low speeds (up to around 50 mph) and between 2-3.5k rpm. The only reason I'm worried about this is because I'm afraid it's oil pump or something. Let me know what you guys think, any diagnosis suggestions are appreciated as well. I don't need to drive it so if the car needs to be out of commission for a while that's totally okay as well. I've removed the supercharger belt and driven around, the noise is still there. However I haven't tried to run it with the accessory belt off yet. That might be my next step. Scanned codes, only code the car gives is for the MAP sensor. Thanks in advance
Last edited by N_Rob; 02-01-2019 at 12:49 PM. Reason: Updated link
02-01-2019, 05:29 AM
#2
The link doesent work for me anyway,regarding the map sensor code,be very careful with that code the car might be running extremely lean under throttle as long as that code is present.Do you have any mods on the engine?
02-01-2019, 12:55 PM
#3
Member
Thread Starter
Thanks for the heads up, link should be working now. The car is stock. It had the infamous hiccup at idle a few weeks ago and the code appeared then so I'm fairly certain that threw it. I did my valve cover gaskets and didn't push the metal vacuum tube all the way into the rubber grommet behind the SC and that's what was causing the lean out at idle. I fixed this and the problem hasn't returned since then so I think my MAP is fine, just haven't cleared the code yet to see if it comes back. I should start monitoring AFR though, the first mod I want to do is wideband and oil pressure gauge install.
02-01-2019, 09:05 PM
#5
Member
Thread Starter
I’ll try that, it only does it when warm though. I can only know definitively that the noise is occurring when driving at low speeds. How long can you drive safely with the accessory belt off if I warmed the car up before removing the belt? Could be transmission I guess, not sure how to isolate that to test for it though. Car shifts perfectly, I know that’s no indication though.
02-01-2019, 10:10 PM
#7
Member
Thread Starter
Yes, that was after me driving home from work. Should I drive it with the accessory belt on and then quickly take it off before the engine has a chance to cool down or what do you think? Doesn’t do the noise on cold, only when the car is up to operating temp is what I’m getting at. I guess driving at low speeds was the wrong way to phrase it, I will hear the noise if the engine is warm and revving in any scenario (Park, reverse, neutral, or drive).
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02-02-2019, 10:58 AM
#9
MBWorld Fanatic!
OP a long screwdriver on alternator as it idles making the noise. Hear it with your ear against the end of the screwdriver? Same trick for water pump. Don't get involved with the belts! Power steering pump. A/C compressor. Each of the idler bearings.
