@udi4.qwick

everything seams to be ok. All of the fans are working, and I don't know what to look for next. Could it be clogged radiator? Car has 62k miles

TOMAS7

Your auxiliary fan should turn on as soon as you turn on your A/C.

When car is cool, turn car on with A/C off. Turn on A/C and see if your fan turns on. If it does then you have other problems.

I'm sure the other guys will chime in and give you more input.

Best of luck.

tozoM8

Your mechanical fan is gone.

TOMAS7

Hey tozoM8 did I get my fans mixed up?

CalG

I just repalced the temp sense switch in the radiator on my daughters A6.

Same symptoms, even if the failure mode included the fan motors that ran constantly until they wore out the motor brushes.

Check all the parts!! High speed fan, low speed fan, thermal switch, power to the system. There is pleanty of cooling capacity on an A8 if everything is working.

CalG

tozoM8

The mech fan will spin all the time, but you can stop it with a pencil. I've replaced it on both of my A8. The replacement fan clutch is under $100 on ebay.

@udi4.qwick

How do I check it?

gondar

then you have a stuck thermostat, internal rad core obstruction, or water circulation problem e.g. (pump, hose, airlock)

if you run the heater full blast it should drop the gauge a bit.

but, with engine off and hot, mech fan should have moderate resistance to turning by hand and not wobble more than 3mm or so. It has to turn fast enough to move some air. it should spin more freely when cold (thermal clutch) for power and noise saving

tozoM8

Start the car (hot) and try to stop the mech fan with a pencil. If you can, you need a new clutch.

TOMAS7

Somehow I overlooked that statement. Thanks for clarifying.