I have a 90 CTD NON-intercooled, 727/3:07 rear 4X4 single 3 1/2" exhaust with a Summit bullet muffler.

It runs around 180-190* down the highway at 65-70 mph.

With a load it's at 190* most of the time.

When I pull hills loaded it jumps up to 200-220*

I replaced the lower hose because it didn't have spring to keep it open, I replaced the rad cap it was old, the rad is clean and free of dirt (1 year old) I pressure washed the entire rad, A/C condensor, and trans cooler.

From what I can gather it's had the pump turned up a bit. I'm not sure.

The fan is working.

It doesn't have a shroud on it I can't seem to find one for it.

So what is normal running temp and what is normal for hauling temp?

I was thinking of getting that cool-blue coolant additive for it.

I'm thinking this thing is running too hot......

Any help would be nice Thanks

Tony

 

do you have the right cap on the radiator? i believe the system calls for a 16psi cap on the radiator. 200* or more is a concern. your thermostat should open about 180-185*. i have plans on an intercooled style radiator. it's a crossflow (and they cool more efficiently) rather than what the non i/c motors have. basically, in the top, straight down and back into the motor.

 

How heavy a load are we talking?

The trans puts a lot of heat into the coolant.

A shroud would help a lot.

The factory radiator is a flawed design, the inlet is directly above the outlet so only half the radiator gets used effectively. Fixes are what Jimbo mentioned, or have a radiator shop install a baffle under the inlet so the coolant has to spread across the whole core.

 

that's a thought. i'll ask my local radiator guy and find out what would be the cheaper and/or better way to go.

 

Well the cap is 16lbs. It's a down flow stock rad.

I have been hauling roughly 7K.

2K trailer and 5K car/truck/van. Plus the 800lbs of tools in steel tool boxes and ladder rack on the bed......

I can't seem to find a shroud for the life of me.

Can I change to the I/C rad and change the top hose?

I'm new to the whole CTD thing since last year so bare with me......

It was a deer damaged rad too and I closed off one tube on the passengers side so I'm thinking that's not helping much......

Should I put a 160 thermostat in it? Or will that be too cold for the winters...... It gets down to 10* around here.

Thanks guys.

Tony

 

i would get a intercooler off of a powerstoke on ebay for 150.00 bucks. they are better intercoolers then the dodge ones. but then u would need a turbo for it.

 

get an auxillary trans cooler. and put an intercooler on it. a shroud would help alot to direct the flow to where it needs to be also maybe check your fan clutch.

 

Welcome to the early 1st Gen world. Combination of transmission fluid heating up the coolant in the heat exchanger and the poor performing downflow radiator. Additional transmission cooler helps, keep the heat exchanger, keep the air to air trans. cooler in front of the radiator and add an additional under bed style cooler with fan. I believe if you search auxiliary transmission cooler you will find some good info on the trans. cooler. You will have to get a shroud fabbed up for that thing, it will help. And, You are SOL for finding a shroud for that year, they were obsolete years ago.

 

maybe try a fresh thermostat,
I've used the water wetter product before, it does help.

 

You can also check to see if it had the thermostat TSB issue. If and when you do that, buy a genuine Cummins t-stat kit, it has a template to check the head for casting boogers etc. The t-stats were hanging up in the bore...

http://dodgeram.info/tsb/1991/07-01-91.htm

 

I have a 90 with a rag and was having cooling issues with a load. Last month I bought a 93 rad(cross flow) and fabbed up a new upper rad hose. Last weekend I drove to Merrit mountain festival(crows nest pass is known for some STEEP LONG GRADES) in 38 degree weather with a fair bit of weight and I couldnt get it to go above half. Although I needed a new rad anyways, it is by far the best mod I have done to my truck.

 

That's a lot of info guys Thanks. I have a line on two shrouds possibly, the one looks like it's off an I/C motor though. If I can't find one I'll make one out of 29ga galvinized sheet metal or piece a couple old Gasser shrouds together.

I'm going to get a new T-stat and see what that does..... I'm laid off again after only 5 weeks back to work and 10 1/2 months off the first time so money is tight. But I'm making money with the truck so I need to have it running right and I don't want it blowing a head gasket.

Tony

 

I was thinking that's the way to go also.....

 

you'll need a thermostat housing from an i/c model if you go with an i/c radiator. it's got a 90* cast into the housing. i'll check with my radiator guy and get some numbers from him. that'll give you a ballpark on what it would cost to go with an i/c rad or adding a baffle just inside your existing one. as far as a shroud goes, what about 2 aluminum pieces to slip in from the top and bottom? that would look nice too

 

Ok thanks for the tip on the T-stat housing.

I guess I could check the local scrap yard for aluminum, but I'd have to get aluminum rod for the stick welder.

As far as looking good yes it would but it make no never mind to me it's a work truck.

So basicly what is happening is when the truck is running 1/2 to 3/4 throttle it's sucking the anitfreeze straight down from the top of the rad to the bottom and never getting through the rest of the rad?