fan clutch going bad???

I have a 1993 g30 chevy van w/ a 5.7l 350 v8 tbi. What do I do to check if the fan clutch bolted on the water pump is still good, or going bad? The truck dosen't overheat, in fact it dosen't come up to temp 195 degrees. Granted, its only 15 degrees out, but I just assumed it was a faulty thermostat. I was wrong. I don't want to put a piece of cardboard in front of the radiator, as it would effect the cooling of the trans fluid. Any help would be great.

Scott

P.s. how long should rear axle seals last if maintained properly?

Fan clutch is a thermostatically controlled fan. There is a bimetal spring on the front that as it heats up the clutch portion should freewheel the fan at highway speeds. Easiest way to check it is when its at operating temp you should be able to spin the fan fairly easy and when cold it will be tight but as you said since its 15 degrees outside it may not actually reach this temp. Putiing a piece of cardboard in the front wont reall effect the trans since the cooler is only in the tank portion, I would try only partially blocking it off and see what happens. As far as the axle seals thats hard to say, there is no real maintanence on these. I've seen them last 50k and I've seen them go at 10k on work vans, load has a great effect on how the last.

thanks for the info. I'll check it tomorrow, after I remove 2' of snow.

I hear ya...31 inches over the weekend. I am so ready for spring!!