Viscous fan unit

After doing some more web site research it appears that my viscous unit may not be buggered after all. It's difficult to find out how one actually works. Some sites say the liquid gets thicker under heat, others say the centripetal force squeezes the liquid into another chamber. Either way, I can stop the fan by hand when the landy is at normal running temperature. Is that normal? Or should I have lost a couple of fingers?

Dave.

Not sure of the exact count.

Research the archive of this group for posts on the subject - by Austin I think.

Well there should be 8 + 2 thumbs, but it's a hellova way to test anything on a car.

At normal operating temperature I'd expect it to be free-wheeling.

Remember, too, that it is the air sucked over the radiator whose temperature is being sensed. Hence if the radiator core is blocked internally or externally the coupling will not detect 'overheating' and will fail to lock up.

If you read back through this group you'll find frequent mentions of viscous coupled fans. When working normally they'll be obviously noisy for about a minute from cold start than begin to freewheel until needed.

I'm not familiar with the thermostat on this model but I think it does not have the skirt as on the 2.25l which is essential to proper operation on that model.

Barring head gasket and other such problems, my money's on the radiator itself being your problem.

For what it's worth the viscous fan on my 300tdi 90 also, can be stopped with little effort at an indicated working temperature. Matter of fact I've never got the fan to lock up ever. I can only guess that it will lock up when towing heavy loads in the height of the summer, I know it never overheats.

Neil

(Reply via NG please)