I've an '85 f-250 with the inline 6 engine in it. Temerature guage runs ...randomly high in it at times. I've replaced thermostat, waterpump, and fan clutch (though none really showed signs of wear), the problem remains. When temperature guage is running hot, it doesn't seem that fan clutch is engaging to fully spin the fan. I'm wondering, is it possible I have a bad temp sending unit, if so, is there a way to verify/test? Also, the truck has no fan shroud, so, i'm wondering if all that open air between the radiator and the fan is preventing the fan from engaging or being useful. Thoughts and advice are hugely appreciated, thanks all.

 

I'm unfamiliar as to whether that year/model originally had a shroud or not. I would assume so......if it did and now doesn't that could certainly hinder cooling/consistency.

 

I have been unable to determine that myself. Repair manual says yes...but the repair manual i have covers 8 years worth of trucks..

 

Pcally. i have a 1985 f150 and yes to the shroud , my gauge used to run high untill i replaced the fan/clutch. a shroud is really needed to force air into the radiator to cool,the actual switch that measures heat is located on the rear passenger side of motor(below the manifold) further back towards the firewall.Up where the hose enters the block ,that hookup is for the computer (sends signal) for control management. Hope this helps , TR

 

Yes, your truck did have a fan shroud and if its missing it can cause problems, especially at low speeds.
I've had two Ford fan clutches fail both by not engaging. On one I replaced it with a new clutch and the other I used a dual electric fan from the JY.
Regards
rikard

 

My 85' came with a single core and a guard that crossed the top of the rad.

Pulled may loads well over its rated limit at 15mph or less and never had issues.

85 F150 XL 3spd od (4spd really) 3.55's


I'd try a new sending unit for the gauge and see

 

"My 85' came with a single core and a guard that crossed the top of the rad." Yup, my '83 did also and it's not really a shroud but a guard like Joe C says. Mine was removed eons ago with no difference in cooling performance.That 'guard' does between none and none whatsoever for the cooling.

 

have you made sure their isnt air in the cooling system?

 

pcallycat,

When the temperature "randomly" runs hot, did you happen to notice that the fuel gauge and oill pressure gauges were also reading higher than normal?

 

Does it do it when its first warming up or all the time?

i had a similar issue that was while it initially warmed up, turned out to be i put the t-stat in backwards

just an image grabbed from Google, but its the same style. The end to the left should face the rear of the engine