How many of you in cold climates willing to live without aux water pump?
 

My new 98 E300D has had the leads to the auxiliary water pump cut. :eek: I can only surmise that the reason that this was done was that a failed aux water pump was adversely affecting the climate control system (yes, this can happen, don't let anyone tell you otherwise), the connector was stuck, so they simply cut the wires. So, I'm trying to decide whether to replace the pump (part is about $200 new) which would also involve installing a new connector to the leads.

The only ill effect of leaving as is is weak vent heat at idle. And of course I have other cars to drive if I need piping hot heat at idle.

What would you do?

I would install a good used aux pump.

Sixto
87 300D

First
 

First decide if it does in fact bother you much. I live in a place on the coast, while not really cold, I like the warm air quickly. That said, as much
as I would absolutely LOVE RollGuy's Sanden kit, I just cannot justify the cost of getting my A/C going. We have about 1 hot week per season here.
It does bug me not having everything functioning properly though.

There's one I can get for $50 on Ebay....but the mileage is unknown so I'm hesitant. I find the pumps last about 70-80k miles (at least on the W124).

There is always the seat heater, but I would want the aux pump installed and working. Perhaps from a boneyard? These pumps may be the same over several chassis styles; I can compare W210 and W201 tomorrow.

Seat heaters are wonderful but your hands and feet still need the heat.

Shertex, I can't imagine you idling enough to need the aux pump. Even if you are moving slowly, the car will still make heat happen, or at least it does in my w126.

Also, I've seen you drive, you don't idle much;)

We could always route a coolant hose through the floorboard with a shutoff valve controlled by an external temp sensor. Anytime its below 50 degrees, coolant is run through a pad in the floorboard.

Thanks for the compliment about not idling much! ;)

Trust me, if I only had one car, I would want that aux pump. When it's 10F outside, it's noticeable. I may ride this winter out and see what I think.

Although I, like you, buy and drive a used MB diesel, it is to be expected that it breaks real often, ;) however, just because it's old, I don't let malfunctioning equipment stay broken very long. I'd get it fixed to OE spec were it my car - this week. RE: aux. water pump malfunctioning......BTDT @ 10F in my old W126. I got 'er fixed in two days.

I'd leave it. As long as I have enough heat to keep the windshield free of fog and frost, I'm happy. I only fix the important stuff.

I checked and the two pumps are quite different; the W210 pump has a 210XXX part number moulded into the housing so it is chassis specific.

the 240D you had a while back didn't have one im pretty sure. Mine doesn't. Didn't you drive that thing over the winter? I can't recall. I doubt this is a major issue realistically.

Unless you plan on installing a light bar, busting out your state trooper badge, and camping out on 95 with the engine running, I don't think you will need it. Besides, if you DO decide you need it, easy install later. Might as well wait and see if the 200 bucks stings

Mine I have no problem with no aux pump in cold temps, and ive had several cars where the aux pump was bypassed for functional issues with no cold weather complaints.

I did not like the heat output in my 85 TD when the aux pump wasn't working.

I would:
Replace the aux pump with a brass union.
or
Spend $75 for an aftermarket seat heating unit. (They're great)
or
Remove, clean, replace my aux pump and wire in a fuse to protect the CCU.

wasnt working as in broken and installed? or bypassed?

how does it work, can it act as a restriction just sitting there?

we get fabulous heat out of our 85 TD seems, at least not a problem at idle really, but there is no aux pump at all, its gone completely and I replumbed straight hose instead.

I think I'll at least go through this winter and see what I think....the heat seats will help, I'm sure.

Hook 12 V dc directly to the pump and see what happens.

Fuse in line with the pump has not been needed since the 123s. They had a design flaw in the 123 where a shorted monovalve or aux pump would fry the CCU controller.
That was fixed in the 124 and later systems with a current limiter that shuts down in the event of a short.

I still cannot fathom why someone just cut the wires unless the pump motor failed shorted.

I took the aux pump out of my 1985 300D because it was spewing a little coolant out of the shaft seal. Since replacements cost >$100, I replaced it with a short length of 5/8" silicone hose (ebay) between the metal tubes, and blue so it looks cool. I get plenty of heat, at least when the quirky temp controller and/or servo-valve decide to respond (my next task). I never saw an electric water pump in any other car I owned, so figured a quirky German thing and not needed.

Just to report back....Needless to say, it's been pretty cold as of late....down to low single digits. I've concluded that I have ABSOLUTELY NO NEED for an aux water pump on my W210. At idle, you can tell there's a drop in vent temp, but it's not nearly as dramatic as it is on a W124....it still blows pretty warm.