Electric water pump - jet of water

Z

Zummerset

Member
Hi all,
Aa part of some pre-emptive maintenance I have replaced the water pump, thermostat and expansion tank on my Coupe. I've run the bleed procedure a number of times but I still seem to have air locks.

Looking on YouTube it seems when running the bleed procedure you can look into the expansion tank and see a jet of water, I can't see any water movement in my tank, should I?

I can hear a high pitched whine of the pump. It seems to spin up for a while, then stop for a while, taking about 12mins to finish its cycle. (It's a Pierburg pump)

Anyone shed any light on jets of water or the sound of the pump in bleed mode?

Thanks, Andy.
 
I had this the first time I tried to bleed mine, as I forgot to unscrew the bleed valve on the upper radiator pipe. I started the water pump, undid the bleed screw, there was a series of huge glugs and the coolant level dropped as the pump started pushing the water around. Worth noting, this was despite having the cap off the coolant tank at the time (which I'd thought would mitigate the need to open the screen, but clearly not in my case).

Maybe you've opened yours already, in which case you can probably ignore that, but if not, it's worth a go.
 
Also worth noting, the cycle isn't just the pump running constantly. If you start it via INPA, it will show you that it is on/off at varies different duty cycles throughout the process

Oddly, ISTA doesn't show you this, despite being newer. But you don't need to worry that it spins/stops/spins/stops etc.
 
Ah, interesting. I ran the bleed with the cap off but not the bleed valve open. As you say, thought the cap off would mitigate the need.

Yes, did notice the pump switching on and off doing it's cycle, so I guess that is working OK.

Will try tomorrow, thanks.
 
Bled one after pump and thermostat change last week, the pump will stop and start when its doing the bleed cycle, I listened to it with a mechanics stethoscope to reassure myself it was actually running. The bleed screw is hidden by the plastic slam panel cover so take that off to access it. Still had air in after the bleed cycle and heater blowing cold repeated but still had air. In the end ran the car to temp and open and closed the bleed screw finally taking the filler cap off when hot and had a massive escape of air which resulted in full heat at the blower. Level checked next day when cold and all is well. Did notice when hot bleeding that temp gauge did start to rise past 12 o'clock and was brought back by the fan cutting in so keep an eye on that as well. As to the jet of water when fully bled and hot you will see the jet just inside the filler cap with it off and engine up to temp. Might aid the bleeding progress if you get the front of the car as high as possible so the filler is at a higher level than the heater matrix.
 
Thanks for another really helpful response.
It seems like bleeding can be a bit hit and miss, I guess depends where the air is trapped and how much of the system was changed.

Yes, front of the car is up on ramps so hopefully that will help. I'll go and try again today/tomorrow.

Thanks again.
 
Success!!!

Ran the bleed and opened the bleed screw. Big gurgle, level dropped massively and the jet of water under the filler cap started. (Front of car is also higher on ramps). Managed to get another 3 litres in.

The pump whine is now quieter and you can hear the water rushing. Will run the car later but not expecting any issues now.

I would have put money on that bleed screw venting the same place as the filler cap, but obviously not.

Thanks again for your valuable advice :thumbsup:
 
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