StephenK

Sometimes when I go out to the garage and need to get something out of the SL600, when I open the door, I hear some kind of pump or something start running for a few seconds. Its rather loud too, doesn't do it everytime, but occasionally.

I just tried it now before submitting the post and no pump noise....

What is it???

vraa

I think it's either your SBC pump or your tranny.
I hear it a lot on a 'friends' M3.

WIldcat465

I hear it too sometimes. I heard in on my '03 SL500 also. Never on my '04 CL

Chris 45971

I know what your talking about but I don't know what it is?

Happens about 1 in every 50 times I open the door; usually, when the car has been sitting in the garage for a day or two.

tiggerfink

I hear it all the time when I open my door on my SL500. I open my hood and all the noises are coming from the SBC stuff on the passenger side near the headlight.

ToonArmy

Yep, I hear that regularly. I don't have a reference, but I think from reading this forum I concluded it was some sort of SBC priming pump.

Scotsman

Yeah, think I read that too. Might have been from Lovin. I hear it now and again.

Sal SL5

I hear it all the time also. I thought it was the suspension...

SLcharger

Yep, its the SBC pump pressing the the pads to the rotors. When the car was left unused for some time, the hydraulic pressure fades away in the brake system, so the same moment you open the door, the car thinks you want to take it for a spin, and therefore prepares the brakes by adding pressure to the system. It can vary a lot from car to car how long it has to stand in the garage before adding pressure, but the reason is that not all SBC systems are leaking the oil to the tank, at same rate.

hbluthi

That is just BAD ***