Frank Wiesmann

I have noticed a whining/groaning sound at lower revs (for example when rolling to a stop, about 1200 revs). It sounds kind of like the auxiliary pump whine sound the car makes immediately after starting it cold (not SBC). I need to turn off the radio and switch to a low fan speed to clearly hear it. It is definitely related to the A/C HVAC, because it stops when you put the fan speed on 0. I was able to reproduce a short burst of the sound when activating the A/C after it had been off for a while. The A/C works fine and the interior fan isn't making any weird sounds. Any idea what this could be? (AC compressor)?? Oh yeah, it is a four zone climate control.

SAguirre

My 2004 also makes this noise sometimes. It sounds like the power steering pump of some Ford cars. This noise really bothered me the first summer and I reported it when I had my car in for service. I also know that it is the A/C compressor because it will immediately co away if you hit the "0" button on the A/C.

The master mechanic acknowledged the sound and stated that it was not yet loud enough to warrant a warranty replacement yet. I have the extended warranty so I am not too worried about it. However, the noise has been getting progressively quieter this summer. I wonder if it is breaking in.

The strange thing about this noise is that it only happens at about 1200 RPMs or in that neighborhood. I will probably have it taken care of this coming spring if it is not completely gone. I think that it makes my car sound like a Ford when it does it and I hate that. Thanks for bringing this up, now I remember that there is something that bothers me about the car. Otherwise it has been quite good up to now, 22,000 miles and going strong. It is getting quicker and getting better fuel mileage.

Steve

murman

We're getting something similar in our vehicle. Very audible just after starting up and when turning the steering wheel. Our E-class just groans like an 80-year-old curmudgeon (sic?) as it drives out of our serpentine apartment complex underground parking lot. (A real luxury sounding thing, NOT...) The sound seems to go away after the car's warmed up... I thought it was a steering pump issue; maybe not?

konigstiger

Mention P-B-46.30/22a APR05 Noises From The Area of Power Steering Pump. The power steering oil level may be low. At any rate, this DTB addresses low oil level, leaks, power steering/radiator line/hose contacting the chassis or any engine components, oil reservoir/filter, and pump - inclusive of bleeding the system.

murman

Again, the man with the answers!

csumt76

Compressor, it exhibits a similar noise as the low power steering fluid only it is not changed when the wheel is turned. It progresses with engine rpm. I can hear it from a mile away.

zergcerebrates

Oh god, thank goodness I'm not the only one that noticed this or have this problem! Its been 2.5yrs and they never manage to hear it! Its so frustrating my noise comes out at low speeds like stop and go traffic, and when I swtich the AC off, the sound is gone same goes with the fan. Upon startup when I turn on the AC the groaning sound comes on immediately...arrgh.

BTW does anyone know what problem it is when I turn off my engine it sound like something been thrown into the engine fan, it sounds like you stuck a paper or cardboard into a fan while its still spinning. The sound only last 2-3 secs though.

Any answers for the AC problem? I'm just so tired of explaining to the dealers and I know for a fact when I hand over my car the technicians won't be able to find the problem.

Frank Wiesmann

Yes, it sounds kind of like a supercharger. Any fixes for this somewhat noisy AC compressor?

csumt76

Replace it.