Flowrate of Aux/Heater water pump?

[Michael999]

Ive decided to avoid purchasing new bmw heater valves and aux water pump due to the overpriced value of $400.

So im going aftermarket, so far ive got myself a 12v solenoid water valve for $30 ($170 for the bmw), and now have a few options for small marine water pumps but id like to get the flowrate as close to the original pump as i can.

The ones im looking at have a flowrate of about 3-4 litres per minute, and having a look at the piping size it seems that ill be refilling the heatercore with hot coolant every 15seconds.

Is this way too high, or is the stock unit a similar amount?

[winfred]

sounds like it should work, not positive about the valve but the pump will probably do


ps old mercedes run almost the same pump maybe you could find one in a salvage yard if you haven't bought the replacment

[632 Regal]

there are tons of these cars being scraped every day, you can get a used one for arounf $50.00 and around $100.00 brand new at bmaparts.com...you need to call them tho.

[Michael999]

winfred, the valve wont connect to the same plug.
The BMW unit is normally open, (apply power to make it close) and the one i have purchased is normally closed.

I tested it with a multimeter and found that the pump power only turns on when you try to turn the heat up, so i will be connecting both my valve and pump to the pump power.
I know i will no longer have dual zone climate control.. but i think its silly anyways :)

Which old mercedes? ill ring a few places and see if i can go have a pull.

[winfred]

most of them in the 80s and early 90s had a pump that was like the bmw pump. all e34s and e32s ran that pump so you have a chance of finding the right unit, all but the earlyest e32s had the exact same valve set up too, the odd early one should work and is rebuildable



Which old mercedes? ill ring a few places and see if i can go have a pull.