Ron E

After sitting for a few hours my '89, when started up you hear the fan locked up and it stays that way until about the time I get into 5th. Then it trails off, and comes back when needed. With the factory guage, it rarely has made it to the 1/4 mark.
On the 96, it's not locked at start up, and all I really hear is it cycling on and off. I never hear it locked for more than a few seconds at a time. And, unloaded, and driven normally it will (again, factory guage) climb near the end of the "normal zone". (maybe 220-230°?) No signs or odors of anything getting too hot. The fan feels fine with some resistance when turning by hand. Is this quick on/off cycling normal or is it time for a new fan clutch (or something else)?
Thanks in advance. You guys are my "support group"

HotRodTodd

No that is not normal. Sounds like its time for a new fan clutch.
That truck should never climb over 195, and normally will cycle between 180 and 190.

Ron E

Thanks. That was my suspicion.

Busboy

If you had a problem with your AC and it was running extremely high head pressures it would engage the clutch fan as it works on air temp not coolant temp. May want to throw a set of AC gauges on and have a looksee before changing out the clutch. It probably is the clutch but it doesn't hurt to check.

HotRodTodd

You might want to stick to bussing tables , as there is NO reason a 96 should be getting 220-230° running empty.

Busboy

I'm retired...but it would get that hot if the condenser was heating it up because of high head pressures, I have seen head pressures of over 600 psi think how much heat that generates. I admit it probably isn't that but unless you check you could be spending hard earned cash for nothing.

Ron E

I looked back at the guage and it seems to end at 230°. It will make it's way to the last white mark. More like 210-220 I'd guess. It will get over there with the A/C on or off. Another strange thing is getting out on the open road at a steady 60, or so MPH doesn't back the temp much if any.

The way the clutch cycles is weird enough to throw some money at a new one. I'll let you know how it goes. Thanks.

infidel

My first step would be to check if the gauge is reading correctly before throwing parts at it.
Infrared temp gun or a kitchen thermometer works great.

Ron E

Well, that just makes too much sense, especially since we own an Infrared gun. It's always been used for quick cylinder-to-cylinder EGT checks off header tubes. Duh! it ain't limited to only that. Thanks!!!!