92 one ton overheating.temps reach almost 220 just pulling 6000# up hill on not a real steep grade. things I do know gages are pretty accurate.truck gage will go to the second mark. electric aftermarket would show almost that much. have replaced it with a good mechanical. it will go to pretty near 220. it would likely go higher on longer hills. now after the engine is operating and warm temp going down hill will drop rite off to 160. I am pretty sure there is a realatively new cummins thermostat. this truck is auto with non air. also on couple hills when it got that hot quickly stopped shut off engine and could turn fan blade quite easy.

 

Have you verified that coolant is flowing/circulating through the radiator?

 

and could turn fan blade quite easy.



My fan clutch wasn't very old, and I had to replace it because it was causing the a/c to not cool properly.

Check your fan clutch, as once it's hot, it should be very difficult, at best to spin.

Next would be to see if the rad is boogered up inside the tubes.

 

Your fan clutch sounds like junk. that is likely your big problem.
My buddy recently installed a Cummins clutch fan on his as he was having bad luck with the parts store ones.

I assume you have a good fan shroud??

If after you change the fan clutch out you still have a problem the next thing that will make a big difference would be adding a transmission cooler. Maybe something like the fan cooled unit that was an option from the factory on the later 1st gens.

I can not get any of my manual trucks to get even close to overheating, but I don't have ATF dumping tons of BTUs in to my radiator.

 

I concur with Oliver and Tee. You need a good fan clutch. Its been a few years since I bought one, but the aftermarket ones really did not work well. Once you get one that works, you will know it . . . the fan really screams when it is engaged.

 

I just replaced mine. Made in USA from Amazon.
clutch

Give it a couple. Years.... I hope.

 

Over the years I have seen radiators plugged up with crud because the owner didn't believe in anti-freeze and ran pure water in the cooling system. Recently I changed the coolant in my system and did a flush with chemicals to do that. I them put 100% anti-freeze in. You wouldn't believe the amount of crud that came out of the system and AFAIK is always had anti-freeze in it. A P.O. had gutted the thermostat however so I replaced it. The thermostat is necessary because without it the engine will not attain proper temperature in cold weather and your fuel mileage will suffer. I have heard that the absence of the thermostat can actually make the engine run hotter.

Edwin

 

Before you condemn the fan clutch, be sure you have good airflow through the radiator, particularly through the center. If the thermostatic spring on the clutch doesn't get the hot air flow from the radiator, it won't engage properly.

 

I run a 50/50 mix of anti freeze and distilled water and about every 2 years or so I remove the rad and flush it with a garden hose....hold hand on bottom outlet and fill...let flow out, flip upside down with cap on and hold hand on upper inlet and fill....let it all flow out...bit of water inside and lay on it's back and slosh from side to side etc.....flush it again. I do this a bunch of times until I see no more crud coming out and then re-install.

But I agree with the others most likely a bad fan clutch assembly, at those temps you should hear the clutch starting to lock up....sounds like a jet turbine winding up.

 

so what fan clutch seems to be most recommended? I have priced out hayden which I really don't want because I believe that's what it may have now also priced out a four season but have not priced out a cummins one.

 

What is the condition of your transmission?
I could watch my transmission temps go from 180* to 250* in a matter of seconds just sitting at a stop light.

next time, try pulling off the highway and put the transmission in neutral and fast idle the engine a bit to cool down the transmission, see if this helps.

My transmission mechanic built me a super duty low stall converter that finally stayed together and moved my temp sensor off the hot line which I have since moved back just to scare myself.
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thanks for all replies. so the trans has a pretty good cooler could be bigger it goes to 180 at max or a bit more lite comes on and starts the fan for it and helps the cooling. goes out usually as soon as it gets more hiway air going thru

 

Take the fan off, start the truck from cold, the either use a temp gun or your hand to check the temps all around the radiator as it warms up. You will feel a cold spot if there is an issue.