Jim Cline

'98 2.8 Avant w/57K starts loosing water: I replace leaking pump along with the thermostat, timing belt, idlers and fan belt. All parts are obtained from Adirondack Auto Brokers with whom I have had extensive good experience. The operation goes OK (first time for me). But: start off from cold and temp needle rises to 12:00 and stays put until (it seems reasonable that) the radiator is full of hot water and climbs to the first ~1:00 mark. Upon seeing this, and noting that the electric fan doesn't start when temp is high, I conclude it is at fault. Shorting the temp sensor leads results in operational fan, so I replace the temp sensor. No joy. I realize that the electric fan does start, but not until the temp is at 1:00. The engine will then cool to normal, the electric fan stops, followed by hot engine. Conclude that the viscous fan clutch is not operational; it doesn't seem to move much air even when the engine is revved. Replace it. No joy. It appears that if I keep the revs above ~2K than all is well, so I'm now suspicious that the water pump is defective, i.e. not moving enough water at low RPM. The original one has a plastic impeller while the new one, from Annex Tecknik (Germany) has a cast iron (rough) one. I contacted Adirondack, and while Mark isn't in, I was told that this is an Audi pump and that the plastic impeller is no longer used.

Before the operation the temp gauge *never* moved from 12:00. Ideas??? I'm not terribly interested in taking the front apart again and not solving this problem.