3.5L rebuild?

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Originally Posted by jasper110

incidentally, how do you test to see if the viscous fan is working correctly?

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There are tests that use a Tachometer for the engine, a strobe light and a Hand held Tachometer for the fanand compare against the manufacturers specs......but if it spins easily by hand - it's f###ed....

.....it should turn with resistance when cold and then when hot should be harder to turn.

warm up the center metal bit with a hot air gun and it should offer more resistance when turned by hand by the blade against its normal rotation direction.

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Originally Posted by justinc

I would actually remove the water pump and check the impeller and the condition of the face behind the impeller for serious pitting etc. The impeller blades actually had broken on one of my 3.5's, causing BIG overheating problems, so much so that I thought it had done a head gasket at first.
It'll cost you about an hour or so with an early rangie engine, and about $6 for a gasket.

<snip>
JC

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When I bought my 76 RR many years ago, the water pump had just been replaced and the old one was with the vehicle. The housing behind the impellor was very badly corroded. I don't know what symptoms led to its replacement, but I suspect it wouldn't pump enough on idle.

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Originally Posted by jasper110

incidentally, how do you test to see if the viscous fan is working correctly?

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Roll up some newspaper, rev motor and poke the end into the blades (do it very gently, dont just jam it in). If it shreds the newspaper it is fine. If the fan stops then it is stuffed.

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Originally Posted by jbarracl

Roll up some newspaper, rev motor and poke the end into the blades (do it very gently, dont just jam it in). If it shreds the newspaper it is fine. If the fan stops then it is stuffed.

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That's a really good idea for testing the amount of "drive" in the VC clutch........of course you have to do it carefully.........another test, but more risky if the clutch is good, is do what an NRMA guy did once on a g/f's Volvo, hold the fan then start engine - if you can hold it then it's had it.......I think he could feel it spinned too easily when spun by hand at first!

In a really stuffed one it will continue turning after you spin it.
A good one will stop immediately.
I could see the one on my son's BMW was stuffed when he turned off the engine and the fan kept spinning.
A good Range Rover viscous will ROAR for about 1 minute after start up as the fluid pools in the bottom overnight.
It should be just a bit firm to turn, eg you should be able to turn with your little pinkie but with a bit of effort.
Regards Philip A