'91 944 turbo water pump operation

[appletonn]

Hi,
please could someone clarify whether the turbo water pump (as opposed to the engine water pump!) is supposed to run every time you switch the engine off, regardless of temperatures, or only at some preset temp?

The car I am buying only appears to run the pump when it is truly hot, not each time you switch off.

Many thanks
Nick

 

[Riverside]

AFAIK it runs for 30 secs or so regardless of engine temp after switching off (this is what mine does). However I believe (never checked) it also has a thermostatic switch to allow it to cool the turbo when the engine is running, (a bit like the radiator fans). It may be that only that circuit is working on yours.

 

[appletonn]

I was afraid you were going to say that !

So there must be a temp sensor or connection that is not doing what it should?

Humph! [8|]

 

[Riverside]

I'd guess the timer relay in the fuse box.

 

[Diver944]

From memory, the relay that has the 30 second timer inside is the G19, but check the diagram on the fusebox lid for sure. Where in the country are you, you may be able to try someone elses relay before forking out on a new one.

There is a nice diagram and guide to the turbo coolant pump at Clarks Garage:

http://www.clarks-garage.com/shop-manual/cool-10.htm

If you are worried then until you get it fixed, just let the car idle for a short while every time you come to a halt.

 

[wibble]

I found two faults on mine; the pump and the relay.
See my thread here :http://www.porscheclubgbforum.com/tm.asp?m=292999&mpage=1&key=wibble&#330546

My only concern would be it does not come on when the turbo is hot after the engine is turned off.

 

[berg944]

It does have it's own thermostat.

My turbo pump has never worked. Don't worry just let the car Idle for 30 seconds.

I believe it all depends how you drive the last couple of miles before you stop.

IIRC the pump is used to stop the oil boiling (when stopped) in the turbo as the deposits then reduce oil flow.

I think the turbo is best to cool down by water and oil......even when you have a working turbo pump.

I purchased a turbo timer (leaves engine running when you leave the vehicle, works out how long for electronically) Never fitted as I am never in that much of a hurry. I was going to put it on ebay but forgot about it until now.

Mike[:'(]