trz1000

I'm pretty sure that I need to check the mechanical fan but would like some other ideas as well.

My 99 A8 gets hot while sitting in traffic. This happened not only when it was 100F+ out side but also at a nice 78F. Of course it took longer at 78F. Anyway, once I start moving, the temperature drops to normal. Pretty standard lack of air flow issue.

The electric fan runs full time.

I've had the car about 2 months now. This issue started up about a month after I bought the car. I found that the oil cooler lines were bad so they have been replaced. Also, while doing the timing belt I replaced the water pump and thermostate.

Any other idesa of what to check besides the mechanical fan? I once heard that you can check those by sticking a pencil into the blades while it's running. If you can stop the fan, it's time to replace it. Any validity to that test? The guys who did the timing belt and such said that the mechanical fan was fine but I'm not so sure at this point.

On another note, the car hunted and thumped since day one. Big surprise eh? Anyway, after changing the tranny fluid it all but stopped. I can still tell it's not 100% but to someone who isn't paying attention it's a non issue. I think I just got lucky and the hunt and thump will return. Anyone else have this happen?

Thanks,

backdoc

Most likely the mechanical fan clutch. My 97 did the same thing last summer. The electric fans ran constanly, temp gauge needle rose when stopped in traffic, and I could stop the fan with a pencil while it was running. I replaced the fan clutch, and it has been fine since. No more overheating, and the electric fans only run when it is really hot outside.
Doug

tonypai

pre facelift = fan clutch. Facelift = thermostat.

ttuling

A bad thermostat, for me at least, first showed up at speed under load

KYNZ

is there a write up on audipages by any chance?

PaulW

Remove it per the TB change out procedure, easy if it's not frozen

-OvO-

I don't think there's anything that requires "advanced" mechanic skilz. I'd say it's about as difficult as assembling a swingset from the instructions.

tozoM8

The fan clutch comes out without removing anything. If you get it lose, it is a 10 minutes job.