Auxiliary Water Pump Leak
 

My 1987 190D was a slow leak at the seal of the auxiliary water pump. Has anyone successfully repaired this pump? I see replacment pumps but no seal repair kits. Any help would be appreciated. Thanks.

Because of the fact that an aged auxilliary water pump can easily knock out the climate control pushbutton unit, I would recommend replacing it.

Good luck,

Larry, thanks for the feedback. The pump is pumping fine as far a I can tell. I am looking for the $0.50 solution before I jump to the $130.00 solution.

$130.00 FOR AN AUX. WATERPUMP LOOKS REAL NICE COMPARED TO $1500.00 TO REPAIR A WARPED CYLINDER HEAD!
MF

Can anyone actually confirm if the 87 190D needs a auxilliary water pump?
Will the climate control system not miss it if its unplugged?
I know some of the 86 and older models don't require and its no issue.
The 87 and up - not so sure.

My SDL has the Aux pump removed and replaced with a 90˚ elbow. Heat will just about cook you out in the winter if you want it to. The OM601 has a very similar coolant flow path, so I'd suggest it would work fine without too.

Not a good idea in warm climate .The aux pump is in the system because the main pump is not good enough to keep the coolant circulating on its own .

Wrong. Wrong. WRONG. The Aux pump is there SOLELY for assisting the heater core. It is a comfort/convenience item, NOT an engine cooling system.

How about this?
I'm concerned about its function in its capacity to the Tempmatic system, as in will it be missed and cause a system malfunction.

In my ‘98 wagon a failed aux pump caused an ACC failure code but didn’t affect system function in warm weather. It was repaired before cold weather so I don’t know how it would have heated the cabin. I can’t imagine an ‘80s ACC system will seize to function altogether if the aux pump is removed. An aux pump electrical fault can fry the ACC PBU in early versions of post-Chrysler ACC.

Sixto
98 E320s sedan and wagon

Not familiar with the 201 heating controls. Does it use a monovalve, or some sort of valve to turn flow on and off to the heater core in a cycled fashion like the 124/126 does? If it does, you probably won't miss the aux pump unless you live in the Arctic Circle.

Nope no monovalve.
Flow is not my concern. The 1987 models and up Tempomatic systems are very sensitive so I'm not sure if its unplugged it will function okay.
The older W201 its not an issue.

Unplug it and find out. If it throws a fit, you can always plug it back in.

I also have an 87 190D. I can confirm that the heating system will work without the pump. I've done this when the pump has shorted out (which makes the entire climate system shut down). Unplug and forget. The only reason I replaced mine is so that when I'm waiting in the car on the cold day, I can turn the ignition to on and bask in the residual heat that's left in the block. For that reason only, it's worth replacing.

And just for general info, the heater valve in your car doesn't regulate temperature. It's either all open or all closed. Temperature regulation is solely the function of the air blend flap in the top of the heater box.

Thanks for the info. My system is still down.
I'm knocking out issues one at a time.
I really sabotage my last step as I forgot to plug in the instrument cluster - that causes the blower fan to malfunction and go into impulse test mode.