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[Kaycee]

Hi
can anyone tell me how i can tell if the secondary water pump is working how is it switched on or is it auto its only because ive seen reference to it  but i cant see how it can be switched on it doesnt make any noise at all at any time i checked book and it said press auto button when engine off and puts heater on this it does but i dont think the pump is running
TIA
Robert

[Darth Loo-knee]

They do usually make a noise, try feeling the hoses to and from the pump as the idea of this pump is to get warm water to the heater matrix quicker so in side heats up quicker than normal. This is why it is called a Winter Pack
Hope that helps

[Kaycee]

pipes are always hot but pump makes no noise is it fused protected

[Darth Loo-knee]

pipes are always hot but pump makes no noise is it fused protected

Of that I am not 100% sure tbh, I would have thought it would be but as I remember there is just a connection on the pump.
I have one here if you want to try it? just cover the postage firstly to see if it works on your car, if so throw a few quid my way, if not send it back to me

[DZB]

Mine is exactly the same as yours - never heard the pump make a noise - the pipes to and from the pump, and the pump, get hot.  I would also like to know what difference it makes, what makes it come on and how to test it.  So if anyone out there knows?
DZB

[Boatboy]

Presume we are talking about the pump fitted below/behind the air filter, and not the one attched to the rad.

If so I have recently been investigating mine, though note I only have manual aircon not cc, so operation may be different.

 At first it didn't work at all, could not get it to operate with any combination of switches. Following advice on here from another member I checked there was voltage at the connector. Should be 12v plus whenever the ignition is on. Having proved power was there I rmoved the pump, undid the 4 screws and found that it was pretty gunked up inside, probably due to a poor coolant regime by previous owners.

After putting it back together It worked! When it's working you can feel it vibrate and with the engine off  you can also hear it.

Sadly, as suggested by JonathanH in response to my original post, it works when cold but not when hot, though I can get it to run by gripping the pump firmly and squeezing/flexing the end near the electrical connector.

On my version I think its purpose is to promote better flow through the heater matrix, particulalry at idle. On cc versions I understand there is an option to continue running the heater when the engine has been turned off.

Try a google for bosch auxilliary coolant pump for some more info.


Steve

[alank46]

Hi
Just out of interest sake, what does the auxiliary pump mounted on the rad do?
Alan

[Boatboy]

Hi
Just out of interest sake, what does the auxiliary pump mounted on the rad do?
Alan

I'm no expert, but I believe it's function is to prevent localised overheating when you turn off a hot (ie fans running) engine, though it's position in the circuit suggests it might only circulate water around the rad.

steve

[Kaycee]

Thanks for that loo Knee but i think it may be working i started it this morning when all was cold and pump is making a buzzing wether its running im not sure but pipes were warm one was warmer than other so i think its must be ciculating may be it only works when engine cold it could be tied in with temp gauge as it got hot long before needle got of zero it does make sense really tho i suppose it will not be needed when engine up to temp i think
thanks anyway ill keep my eye on it

[Darth Loo-knee]

Thanks for that loo Knee but i think it may be working i started it this morning when all was cold and pump is making a buzzing wether its running im not sure but pipes were warm one was warmer than other so i think its must be ciculating may be it only works when engine cold it could be tied in with temp gauge as it got hot long before needle got of zero it does make sense really tho i suppose it will not be needed when engine up to temp i think
thanks anyway ill keep my eye on it

If you can hear it buzzing I would say it is working mate

[Andy B]

.....
On cc versions I understand there is an option to continue running the heater when the engine has been turned off.
 ......

I thought that was just for facelift cars.  :-/ :-/