jturkel

I was just putting my car in neutral in the garage to push it backwards and get a wire out from underneath it. Obviously, to put it in neutral, you have to put it in the accessory position just before the position that starts it. When I did this, about a second in, i heard this weird buzzing noise coming from my engine bay. Upon closer inspection, it appears to be coming from the passenger side towards the front of the car. The noise would last for a second or two and then just shut off. I have never noticed it and have no idea what it is. My car was having start problems the other day....and for those of you who havent read that thread, it would turn over but wouldn't start. It works now, but I have no idea what was/is wrong. Maybe this is related?



disregard that red circle that is in the picture. i circled in BLUE where the noise is coming from. i cannot exactly pinpoint it, but it is coming from that general idea. any ideas?

calimax

yup, it's likely to be that pump up against the reservoir. (not the one circled in red)

jturkel

what is that pump?

calimax

my guess is that its just another circulation pump for the coolant one of the hoses leads to the water pump.

hooleyboy

That is an air pump, mine make a loud whine from time to time. The air pump is used for emissions. C55 have them on the front of the engine were your SC pulley is. I just had mine in my hand today.

calimax

the big pump circled in red is the emissions pump, but the little one above that one passes coolant through it.

1qikctr

That is a smog pump.

jturkel

wait , so which pump is which?
the air pump is the largest (the one circled in red)?
and then there is the emissions pump, which i'm guessing is the same thing as the smog pump? which one is that?

which one is the coolant pump?

grrr..

mike.....mine isn't making a whining noise though.....its like a low sounding bzzzzzzzzz noise. its weird. idk.

c32used

Well I know it has something to do with a pump that feeds the charcol canister..buzing noise means it works.

jturkel

hmm, so this may be a normal noise then that i have never heard? weird.....does anyone else have this noise when they turn the key to the position just before the start one?

TemjinX2

yeah have the same noise..too. it should be fine. the coolant pump is the intercooler pump below the passenager head light. its the one everyone replaces.

jturkel

hmm....but isnt that closer to the heat exchanger? or is that pump next to the IC reservoir the coolant pump? the noise is coming from near the IC reservoir (height-wise with respect to the ground and near the general blue circled area)

TemjinX2

the intercooler pump is below whats circled in blue or directly under your passenager head light. But it only engages when your supercharger is engaged.

the noise your hearing is something else..probably what c32used said. I have hear it too when i put the key into the second position and not turn on the car.

jturkel

yah, i thought the IC pump was lower

that is reassuring that someone else has this noise. thanks

TemjinX2

np josh..any word one when your gonna have the belt wrap kit off? My friend is gonna shave the oem pulley from 74mm to 63.5.

moosejaw

Does the noise sound like a tile saw? Mine does that for like five seconds in the morning and then shuts off?

60n5pt1

I heard that sound one time when I started the engine one morning. It went away after about 8 -12 seconds. That afternoon after work, I headed out to my car and fired it up. Same thing. I popped the hood and saw where it was coming from.
It was a hose with air blowing out, that came loose, leading to the alternator. Location; above the right headlamp next to the radiator.
Put it back on and never heard it again.

But, I did have an siren alarm go bad. It just went off on its own. The sound came from the right front passenger wheel well, between the brake and the firewall. Even after disconnecting the battery terminals, the sound kept going on and on. The weird part was that it didn't even sound loud enough to call attention.
Long story short, an MB shop replaced it and now, my car has a bird chirping sound when I lock and unlock the car with the remote. Cool I think.

JG26_Irish

Funny that it took this long for this to show up if it is normal??

I took the C32 out last night and when we stopped for dinner, I hear the same low frequency buzzing noise under the passenger side of the hood. It was buzzing after I shut off the engine, pulled the key and continued for several minutes after I locked the doors. On the way home it did not repeat. I took it out again to try to duplicate the sound but never hear it again.

So is it the smog/air pump (not a big deal) or the IC coolant pump? I know if the IC pump fails the SC will not engage right?

Irish

denice25

I think its a pump....