Secondary Water Pump
 

My '88 260E sec H2O pump is seeping and am looking to either replace or fix. From what I have gleaned from the search feature not much success from trying to fix. Anybody happen to have a good one they'd part with? Or a supplier for a not-so-expensive replacement? Thanks for any replies. :)

You could always bypass it. As far as I know, the only loss will be the "Rest" function ( if you have it ) and perhaps a bit colder heat at engine idle.

True. What do you mean by "rest" function? Not familiar. I'd really prefer the device to function as designed but I hate the idea of spending $$$ for a new pump!

Yep bypass is an option .But aftermarket auxhiliary coolant pump, is not expensive i had to change mine last year for leaking seals .You can get a repair kit in usa but in the sinking island [ UK ] i was not able to . Easy fix to put new ones in ,but then it might need brushes replacing as well ,this to you can do yourself.

optimisation, thank you for your reply. My endeavors into locating new or after market pumps has not been very successful, would you have suggestion where I might look - or a link? I have looked on Pelican but unable top fond one there as well. Thanks again for your help!

The REST function is Residual Heat Utilization. ( MB likes abbreviations )

It works like this: Drive the car, park and shut off the engine. Press REST and the heater valve opens, water pump turns on and blower runs at low speed. This keeps the car warm until the engine gets cold or you come back.

If you do replace the pump, be sure to add a inline fuse. Older systems didn't have a fuse and if he pump locks up, it will literally burn down the heater control unit.

Also do a search for " blower motor resistor fire ", some cars would burn due to leaves getting on the blower resistor.

Also, bypassing the pump only takes a piece of hose or a heater hose connector. This would stop the leak and allow you to source another pump. This leak might lock up the pump or start leaking at a greater rate causing an engine overheat condition.

It looks like it might be in the cards for me to bypass if only temporarily. Thanks for the replies and suggestions 😎

Oh, I forgot to mention,i assume it doesn't have the Rest feature since there isn't a REST button to potted!

You should undo the electrical connection on the pump. Eventually, water will find it's way into the motor, and if it shorts, the entire system shuts down.

I will do that. Thanks MxFrank

On my '05 ML, I was able to swap in a VW pump. It's also Bosch, and nearly a perfect fit, but half the price. The difference is in the cap with the pipes of slightly bigger diameter, which was actually swappable with the MB one - just unscrewed. Not sure if this will work for your museum piece, but google some pictures and check.

Thanks Hirnbeiss, I'll try tip get a pic and do that but for the meantime electrical is disconnected.

85 l go to your Ebay site USA put this number in search 151721403865.

Here's the VW pump. It doesn't look quite as plug and play on your model, but with a little wiring work it may do the job: Audi, Volkswagen Engine Auxiliary Water Pump - Bosch 0392020039 - Free Shipping