How do you know when to replace this pump? Mechanic says to do it now (120K) because it could damage the climate control system in the dash.

Neil
124 300TE 4matic
126 300sdl

Soccer,

Yes, the auxilliary water pump can indeed cause damage to the climate control, however, why replace it if it's not bad.

Check the pump to see that it does NOT draw more than 1.3 Amps. If it draws more than 1.3 Amps, replace it.

I personally think that replacing parts on one car at a particular mileage because the same part failed on other cars at that same mileage without testing them is wasteful.

My auxilliary water pump on my '88 124 with 170K miles is still working fine. I checked it not too long ago for current draw and it was fine. If I had replaced it at 120K miles it would have been a waste of money and effort.

I believe mine is still in good shape, because I have kept the cooling system flushed and clean. If your cooling system has gotten dirty and been ignored, your pump may not pass the test. But it doesn't cost anything to test it. Give it a shot.

Good luck,

------------------
Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

The amperage test is the only way to do this.
Be sure to test and replace items only as needed.

------------------
Benzmac:
Donnie Drummonds
1992 500E (very soon I hope :)
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Doing some necroposting here, hoping to get some answers on these
W124 Secondary Water Pumps.

I have a 1989 W124 300TE and the secondary pump is seeping/leaking water but it appears to be working correctly.

Can these secondary pumps be rebuilt?

Also, when I look up the secondary pump on various sites it shows two and I am not sure which one to get, does it even matter which one I get? what are the differences between the two? One is in the 80-90 dollar price range and the other is more like 130-150 price range.

you can probably get one fairly cheap at the boneyard....

i have a spare if you are interested.

Heck yeah, If it is in good shape I am interested!!!!

To anyone else checking this out, I would like to see any answers you have on my questions. It seems goofy that you can not fix one if it is leaky and I am interested in the "why" and "what's the difference" between the two they offer.

Easier to replace, and lee has great parts and fast shipping.