I have a 1998 X308 with a noisy aux water pump.
The unit runs continously even if only the fan is running with no AC
I understand that this is what it is upposed to do.

What would happen if it was just diconnected while I hunt for a replacement.
From what I can see it is just a centrifigaul impeller so my theory is that water wil still flow but
more slowly.

Can anyone shed some light on this and also let me know what alternatives you have used.

 

From reading other people's issues on here, it'll mean if you do want any heat there's naff all flow of hot water till about 3k rpm so your heater will always be cold.

 

Thanks. I will runs some tests and post results here while looking for a replacement.

From what I can find, the Bosch 0 392 020 034 may be a possible alternative.
So far, I havent found much info on the specs re the dimensions, connector sizes and flow rate which I assume are the important parameters.

 

I have a used working aux heater pump I kept around as a spare, that I'd be willing to sell you. It worked when I applied 12v a couple months ago, I can double check before sending it out as well.

Send me a PM if interested

 

Thanks for the offer but I suspect postage to Australia will make it not feasible

 

Aux heater pump hose outlets are weird 16mm diameter. I have bosch 0 130 002 067 reserved to it. It has 15mm outlets. Outlets may be possible to make thicker. I have not got an answer though why oe pump has magnetic inplerrel. Afermarket ones do not have magnetic.

 

5/8” heater hose is roughly 16mm. If the hose is just a smidge too small, a hair dryer and some silicone spray should be good.

 

Finally had a chance to run tests.
It seems you can run without an aux pump (and the annoyingly loud whine).
I tried disconnecting and going for a drive in the morning.

The heater still works however it takes longer to heat up and
varies with engine speed. The drives was approx 30 minutes with speeds mostly around 80km/h with some 60 km/h and few
traffice lights.

The same run later with the aux pump connected shows the even ramp of temp and much more stable pattern which is to be expected.



Temperatures show are at the right hand vent. Fan speed was 2 bars, temp was set to 22 degrees.

Now to find a replacement pump .....