Coolant Auxiliary pump
 

After replacing the stat and achieving the ideal operating temp, my heat still not up there. So, tested the aux pump by disconnecting it and applying 12v power from battery. Every time I connect (either polarity), I hear a light thunk. I expect to hear a wrrrrrr sound if its running. This tells me that its probably seized. Do you agree? What is the life expectancy on these pumps anyway?

I am wondering if it can be un-seized? Has anyone ever tried taking one of these off and opening them up to see whats making them stuck?

If its the original it has probably seized by now, install a fuse in the cord to the pump to save the CCU from burning up (a seized motor draws way more juice than a running one...a la torched circuit board), my pump is on its way out (sqeals on occassion, but has been running ok lately...) I have a spare on hand for when it does finally die/blow my fuse, I installed a 1A fuse and holder in the cord from the pump itself, cost about $4 at radioshack, way less than a $400 CCU! :eek: .

Opening the pump will only show you how coroded/dead it is, not worth it, find a used (or new) one somewhere.

Yes it should whir when power is applied...

Can I just disconnect the power (unplug it at the connector) for now?

I unplugged mine with no ill affects. Still have great heat too.


85 300td
85 300d
83 300d
81 240d

Hi

I have a Euro model that doesn't even have an aux. water pump. Can anyone reccommend a cheaper replacement pump that I could put in?? I have good heat also, I just want one for use with a WVO system.

Peter

The aux water pump was added to the climate control system in response to whining from customers who said the heater didn't put out enough heat at low engine speeds (i.e., around town, low speeds, lots of sitting at traffic lights, cold weather, etc.). The main water pump doesn't send enough hot water through the heater core, apparently. I suggest removing the aux pump and replacing it with a short piece of copper pipe. If your heater still keeps you warm in your climate and style of driving, forget about replacing the pump.

The junkyard is full of 'em. I pulled one from an old Audi 5000 turbo to use on a Vanagon/VR6, the Volkswagen VR6 also used 'em, but they are a slightly larger hose connection and different wire-plug. Mercedes of course uses their own plug, not difficult to graft if you're looking to repair on the cheap. I got my spare from a 190E, same pump as the diesel and there are lots of 190Es around.

- Jeff
190DT

I thought of doing the same thing... might be worth a try... while i check the pump...

Aux pump
 

For the true tinkerer... you can open it up by removing the 2 long little bolts and pull the steel housing that contains the magnets off the white plastic armature/brush assy....leave the front part alone....there are actually replaceable brushes mounted in the white plastic piece that the main steel body attaches to....I just rebuilt mine....will have to see how it holds up....mainly concerned how watertight the shaft seal is now....

Are the brushes pretty standard size? Can you get em anywhere?

Also, am I understanding you to say that you left the pump portionin place and found a way to remove just the motor from the car, or did you remove the entire assembly?

pump...
 

This is a used pump that is out of a vehicle...the brushes are just small alternator size brushes ....I just file close ones down for a good fit...They are very close to my 89 Mitsu 4WD pickup truck alternator brushes....about 3 bucks at auto parts stores....there was rust & scale inside the steel housing that I cleaned out and it was very slow before the rebuild...after the cleaning and lubeing it spins great now....had about 3/4 of the orig. brushes left so i left them on...but I have the new ones for next time if this thing pumps without leaking.....

price just got a bit cheaper.....

0130002070 Bosch
Water Pump; Electric Auxiliary Water Pump $74.47 New!!! Half of what everyone else wants...

From where?

fill the pump motor with ATF(wonderful stuff)let it sit overnight and drain thoroughly.try turning the shaft with a pair of pliers.easy does it!once you get it turning attach to 12v and see if it runs:idea2: