Radiator fan not working - suggestions?
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Radiator fan not working - suggestions?
So, after a month of teardown I took the Quattro for a spin today for the first time since getting it home. I filled it w plain water as im going to flush it before filling w coolant. At one stop the radiator gurgled like it was boiling and the engine felt warm. Id watched the temp guage vary from 1/4 to the midpoint and the midpoint was where it happened to be when i stopped. I have never heard the rad fan on. Any common thing to chk on the fan or its circuit? I still have not found a bentley, so any suggestions welcome. Tx, DougM
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From: Canada
So, after a month of teardown I took the Quattro for a spin today for the first time since getting it home. I filled it w plain water as im going to flush it before filling w coolant. At one stop the radiator gurgled like it was boiling and the engine felt warm. Id watched the temp guage vary from 1/4 to the midpoint and the midpoint was where it happened to be when i stopped. I have never heard the rad fan on. Any common thing to chk on the fan or its circuit? I still have not found a bentley, so any suggestions welcome. Tx, DougM
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From: CT
Could be the fan switch test it by jumping the connector with the key on
http://www.sjmautotechnik.com/troubl...oling.html#fan
The plug on the fan itself should be checked too as over time the female connector can become loose breaking the connection inside the fan.
http://www.sjmautotechnik.com/troubl...oling.html#fan
The plug on the fan itself should be checked too as over time the female connector can become loose breaking the connection inside the fan.
Thread Starter
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Thanks - great article. So the switch at the bottom of my main rad is the thermo switch, and there's a resistor pack to check and then the fan motor itself. My fan spins smoothly, so no bearings seized, etc. I'll do the checks if I get a chance tomorrow.
As for coolant, I flushed out the smaller secondary radiator while I had the bumper off by repeatedly reversing full hose flow and only after about 8 cycles did the water stop coming out with some crud. So the main radiator is doubtless in need of the same treatment as is the heater core. Fresh water pump. Fresh corrrect thermostat and O ring.
Anyone know of a coolant system flow diagram so I can pull the correct hoses off to reverse flush the radiator and the heater core? Thanks.
DougM
As for coolant, I flushed out the smaller secondary radiator while I had the bumper off by repeatedly reversing full hose flow and only after about 8 cycles did the water stop coming out with some crud. So the main radiator is doubtless in need of the same treatment as is the heater core. Fresh water pump. Fresh corrrect thermostat and O ring.
Anyone know of a coolant system flow diagram so I can pull the correct hoses off to reverse flush the radiator and the heater core? Thanks.
DougM
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Joined: Mar 2005
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From: CT
No resistor pack on the 90 20v. That link is generally for the large chassis cars but the info about testing the thermo switch is the same. http://20v.org/ has more info directly related to the 90 20v.
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IIRC you can test the radiator fan by jumping the wires on the temperature sensor all the way down on the passenger side of the radiator. The middle prong is 12v and the top and bottom prongs are high and low speed. just jumper them to see if anything happens.
I tested mine by using an ohmmeter and putting it in a pot of boiling water.
I tested mine by using an ohmmeter and putting it in a pot of boiling water.
AudiWorld Senior Member
Joined: Sep 2010
Posts: 623
Likes: 5
From: Cincinnati OH
IIRC you can test the radiator fan by jumping the wires on the temperature sensor all the way down on the passenger side of the radiator. The middle prong is 12v and the top and bottom prongs are high and low speed. just jumper them to see if anything happens.
I tested mine by using an ohmmeter and putting it in a pot of boiling water.
I tested mine by using an ohmmeter and putting it in a pot of boiling water.