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91 200 Q Turbo Coolant Pump

For all of you out there with the 3B engine (20V turbo) that don't hear the
cooling fan come on after you shut it off, here's the skinny:

Many of us do not have the radiator cooling fan come on after shutting the car
down. There is a seperate "Turbocharger thermoswitch" that does two things:

1. Turns on the radiator cooling fan
2. Turns on the turbocharger coolant pump (located just besides the dipstick,
looks kinda like an idle control valve)

The procedure in the bently calls out running the engine until the cooling fan
comes on (if I start mine from cold, and leave it at idle, it doesn't get to
this point within 15 minutes with the hood open, probably due to 27 radiators
and coolers providing excellent cooling). Then turn the engine off. After
approximately 5 minutes, the electric coolant pump and radiator fan must switch
on. If NO:

1. Disconnect wires to thermoswitch and connect to each other. The electric
coolant pump and radiator fan must come on.

2. If no, repair break in wiring using appropriate wiring diagram (not likely

3. If yes (most likely), replace thermoswitch.

The thermo switch is just inboard of the oil dipstick, it is mounted vertically
and the wires come out of it on the bottom. It has two seperate wires connected
to it that have spade clips on them.

My thermo switch is toast (at least by procedure, didn't wait for the engine to
warm up, just jumpered it out, less burns that way).

Get those new switches boys and girls, you don't want to toast your turbo
because of a $20, 30, 40, do I hear 50 dollar switch. I wonder how much Audi is
going to kill me on this one.

OBTW, some coolant will  come out when you pull it out. Make sure to have more
on hand.


91 200 q with bad coolant pump thermo switch

Paul Waterloo                    TEL: (860) 267-7714
HydroAire Incorporated           FAX: (860) 267-7387
875 Old Hartford Rd
Colchester, CT  06415          EMAIL: 74543.407@compuserve.com