heater pump noise? - PeachParts Mercedes-Benz Forum

kwc · #1 10-06-2009, 09:50 PM

I have an 98 ml320. Recently, what I think is maybe the heater pump/moter is making a bad noise randomly while driving. Sometimes it continues after the car is turned off. Sorry for the lack of info but I'm a woman trying to trouble shoot my car. Its next to the battery and has hoses coming from it that go to the dashboard.The noise reminds me of when the impeller in my fish tank filters needs cleaning. Kinda a humming squeek sound. If I wiggle the unit, it stops.

mbdoc · #2 10-07-2009, 08:15 AM

That is the auxiliary water pump. Try disconnecting & see if the noise goes away.

You will need to replace it if it is the cause of the noise.

kwc · #3 10-08-2009, 09:11 PM

Ok, so aux. water pump. What excactly does it do and how important is it? If I cant get it replaced for awhile am I hurting my car? ( I'm broke right now) Is it easy to replace if I try to do it myself?

YuCrew · #4 10-08-2009, 09:34 PM

Easy to replace. Designed to circulate water about 5 minutes after engine shuts down. I will bet there are a quite a few not working anymore that the owners don't even realize are no longer working.

kwc · #5 10-08-2009, 10:35 PM

Well, mine runs fine for the most part. It makes a bad noise while driving occasionally. Loud enough that I can hear it while driving down the road. Its kinda a cross between a squeal and a hum. Hard to describe. Once it continued to make this bad noise for 5 minutes AFTER I turned the car off. I recognize the quiet hum for a few minutes when the pump is running after I turn the car off,but this is a BAD noise! As long as I'm not killing my car by not replacing it ASAP, I wont worry as much!

mbdoc · #6 10-09-2009, 08:28 AM

That water pump is important in the cooling of the engine & for flow thru the heater core.

Depending on your climate area? may not be needed for several months.