Re: Aux. Turbo pump checking

[Dave Head <dhead@sundial.sundial.net>]

At 10:33 AM 2/25/97 +0000, you wrote:

>One question I have is how do you know that the pump is working (i.e. 
>bad relay or switch) since you can't tell if it is actually pumping.
>
>My old pump would run when connected to 12V but the impeller was frozen 
>up. The impeller is magnetic coupled to the motor so that the motor can 
>be running but the impeller is sitting stll. I think the only way to 
>check for sure would be to disconnect the coolant hose and look down 
>into the plastic housing while connected to 12V and see if the impeller 
>is turning.
>
Hmmm - the two I've ripped apart were fully shafted w/packing, etc... I've
seen one froze up, but most common failures are:
1.  Impeller vanes soften and break off.
2. One of the snouts harden and break off.

Quite easy to get a 3" long PVC hose coupler and connect up to the inlet and
outlet, then you have the pump out to test. The thermoswitch is right on the
head water inlet - two blade. That pump should only run (w/low speed fan
ops) when engine temp is about 1/8" past 1/2 scale on temp guage or higher.
It should only run to slightly below 1/2 scale. I can't remember the
numbers, but 95C on and 85C off sound familiar. Connect the two wires on the
thermoswitch and it'll run anytime. Put the wrong thermoswitch in and it'll
run til yer battery gives in (BTDT). If the electronic after run relay is
toast, either the fan (low speed), the pump, or both won't work. As an
aside, the after run relay is important as it carries the low speed fan
signal for AC ops, and pases the increased idle speed during AC ops on to
the idle control circuit.

********************************AUDI FAN***********************************
                                   EMCM(SW) Dave Head  
87 5KCStq 187K miles and counting... 1.7 bar boost - Whee!
                Maitland, Florida   Hey! There's no mountains here!
******************************************************************************