Well, the pump is at stock level, k an N, radiator looks cloggy, like the veins an all, and a denny t pin. The thing I dont like about the stock temperature guage is it has no numbers, but the truck stays on the middle notch all the time, until I get on the highway at 75 mph, then it takes about 20 minutes and the guage creeps to the next notch. How much warmer am I really running? what suggestions do you guys have? Thanks

 

Has the T stat been changed. Has it ever had a manual gauge put on it to see if the dash gauge is correct. If the T stat has been changed make sure it is OEM, not aftermarket. There is a differance. Radiator might need boiled out and the coolant replaced..

 

how much hotter is the truck heating up between 1 dash mark? And I have only had the truck a year, but I would think it has not been replaced, truck was not taken care of.

 

I dont think any two gauges read the same I know my truck is at 180 when the gauge is right in the center. Only because I checked it with a temp gun.

 

And thats why I asked if it had been checked with a manual gauge. Mine at temp will hit the first line, cycle ALOT. Then settle to the first line...

 

I will be interested to see what you find. Mine does about the same thing, except on the highway with AC I am sure I am running just shy of boil over. New water pump, new radiator, recent head gasket, checked the condenser and intercooler, both are open to airflow. non Cummins tstat??, might require a trip to Cummins.

Now my fan clutch is seized up, sounds like an airplane at 75, I have a friend who likes to put Cummins in old Fords, he never seems to have room for a belt driven fan, so he does not run any fan at all and I have never seen his trucks over heat, we live in the sticks so no stop and go. I am building a dual electric fan for mine so I took the belt driven fan off to take measurements, decided he can run with no fan so I will try it, my truck runs hotter with no fan on the highway, gauge nearly pegged, early morning temp of 55 degrees, 75 MPH. a properly operating fan clutch should mostly free wheel at speeds over 35 MPH anyway, so my locked up fan clutch is actually doing me a favor (not fuel mileage wise). gotta go to Texas in a month so I need to solve this.

Could a cheap T-stat cause me all this grief? As I read what I just wrote I am starting to believe that just may be the problem. I will know soon enough and post back my results, untill then post up your opinions/suspisions.

 

It has been miserably hot here in Southern California lately, so today I had to make a trip out towards San Bernardino where it is even hotter, I was on the freeway 70 MPH that quickly turned into a parking lot so I got off onto the surface streets.



I knew it was hot but Geez, come on.



But it was still nice and cold inside the cab as I was now driving on the surface streets with the blower on the first click down (your High Speed).

I looked over to my daughter and she was all huddled up and shivering and said I’m cold dad. So I added a little heat.



This is where the temperature pretty much stays in traffic; I think my 2) 16-inch condenser fans are doing their job.
https://www.dieseltruckresource.com/...s-t250585.html



However I have noticed also that sustained speeds above 75-80 it will move up to the next mark until I slow down and then it drops back down. I think I may be turning my water pump too fast at this speed or maybe it is added heat from my torque converter.

I also turn on the electric fan on the remote oil cooler and it seems to help control the temperatures, but unless it in the 90’s or above it usually just stays in the middle.


Yes a bad thermostat could cause you to overheat as could air in the system,
Is the spring still in the lower hose?
Assuming you do have a fan shroud.
Working 16# “recovery” Pressure Cap?
To high of antifreeze concentration.
Slipping torque converter.
Overcharged A/C
Are you using R-134a or R-12?

Jim

 

Hey Jim, how can an overcharged AC cause your truck to run hot? Sorry for the highjack, just curious. That may very well be my problem as I am experiencing the same thing.....

 

Mine has been running right at the 3rd line for about a year. I think it's too hot but who knows without a manual gauge, duh on my part, I have a point and shoot temp gun. I'll check it today. Like Jim Lane the temps here have been 100* to 108* with the humidity from 70% to 85% so yea it's hot and muggy.

 

You need a cummins T-STAT!!!

 

The dodge radiators are much smaller than the ford radiators. You really need a good fan of some sort. The factory fan with an OEM fan clutch works great everywhere except for stop and go with low rpms. That's where an electric fan would come in handy, mostly for keeping the AC cool.

I believe an AC system with too much refrigerant will have excessive pressure and put excessive heat into the condenser. Pressure=heat.

 

^^^ there's the reason for an overcharged system keeping the truck running hot

 

Thank you sir - learn something new every day.

 

My gauge sits right where yours does in the middle, no AC and locked up fan clutch, before the clutch locked up it would sit in between the next 2 marks, AC on it would sit right on or just past the last mark, not the fat one by the H. Could it just be the 4.10s and 83-85 MPH on the highway. Maybe it is just turning the WP too fast, had not considered that before.

Maybe it's time to start researching a bigger radiator, if not for the intercooler I would just put my 6.2 GM radiator in it, that would keep it cool.

Will stop at Cummins tomorrow night for T-stat and seal.
Hose spring, yes.
Shroud, no. but my problem is only at speed, stop and go not even an issue, shroud should not matter.
Cap, new and working.
Antifreeze, 50/50 mix, with distilled water, too much mineral in the well.
Converter, NA. Manual.
AC, NA, non AC belt, trying to diagnose a belt eating problem, new tensioner fixed it.

 

Justin had the same issue Thats why I asked about the T-stat.. Keep us posted when you get it changed out,see if it runs cooler...And YES to answer your question. A cheap T-STAT will cause that problem.