My temps seem to be all over the place...today while driving to work my freeway temps were 199 and wouldn't budge, city temps were the same and idle was 204. Checked the fan today before starting the truck and found that the fan did spin and it had a little resistance in it. This is normal right? These temp fluctuations are annoying...I want to get my truck ready for spring/summer and I want to make sure it's going to be safe to drive on my adventures. Radiator cowling plastic is all there, might as well replace the pressure cap to be safe. How can I test to see if the radiator is clogged and did I test the fan correctly?
There is no real test for a viscous fan. Typically, they will spin with a little resistance when cold. When you start you should be able to hear the fan spin up, as it distributes the fluid, then after about 5-10 seconds it should go quiet. It is often hard to hear that though. When hot (switch the engine off first!) they will have more resistance.
Why are you worried about this? Your temps are way within spec. A D2 will generally run at around 194-196, but an indicated 10 degrees higher isn't normally an issue. Changing the stat to a lower temp won't necessarily change the measured temp that much due to the way the system works. Look in the Rave manual for how the D2 system works (different to a D1 or RRC) and you'll see why. If you're at 210-220, you might have a bigger issue.
Graeme Ware -- San Carlos, CA
1990 Range Rover Classic - LT230 Transfer box, Warn winch, 2" lift, 235/85-16 Dunlop MUD Rovers, "Blue Submarine"
1996 Discovery 1 (R380 Manual Transmission, Ashcroft under-drive, RoverWare rear bumper, 33x12.5-15 BFG ATs) -- we call her "Katrina" -- Fordyce 7.5 mile survivor
1999 Discovery 2 (D1 CDL Linkage, 265/75-16 BFG A/T KO, RoverWare front and rear bumper)
1993 Jaguar XJS convertible; 1971 Triumph GT6; 1959 Morris Minor convertible
other assorted British pot metal ...