I had problems with my 1988 f250 7.3l with banks turbo overheating...replaced the fan clutch,thermostat, and antifreeze ..all to no avail. Ran cool until I pulled my 4000# camper.This is what I dug up after days, weeks, months of looking on this great site as well as others.
1.With mine the radiator fins were clogged with junk and paint overspray (was repainted)...have to have a clean radiator for it to work.( A/C condenser too) 2.The truck had red and green antifreeze mixed in the system at one time...this causes a crystaline buildup as well as something that looks like snot. You need to chemical flush the system and pull the drain plugs(2) out of the block to get the system clean and working the way it should.( I use Shell antifreeze made for diesels) 3. If bars leak or any thermo stat besides a tested factory one was used, it could be a hung up stat. Factory stats have no bypass,none is needed because there is a check ball built in the t-stat housing. Check the stat in boiling water for operation. Bars leak likes brass and will accumlulate on the stat and can cause it to hang up. 4. The factory fan clutch and after market clutches are NOT made ideal for towing. I had put a new one in mine ( from advance auto)...I returned it and got a modified one from MS Tech. It is made to lock up a little sooner, also at a lower RPM.( they also sent a 180 degree t-stat...I never installed it...it is 10 degrees cooler than factory) 5. The heat in the water jacket is directly related to the heat of the exhaust. So a cooler running engine means a cooler water jacket. Check to make sure the engine is set up properly on timing and fuel.. My pyrometer goes to 1050 for a while and the engine water temp pegs at it's max. Not releying on the factory gauge, which is resistance buffered and using a aftermarket guage in the back of the engine ( 190 norm), 242 is the max temp before engine damage can be expected. The back of the engine is the hottest, especially with the exhaust running up to the turbo as on my particular truck. I have heard that installing an air dam ( which trucks of this era did'nt really have), changes the air flow in the engine compartment and helps with the cooling. 6. Just a note, my truck had dealer installed A/C....so the radiator is one that is different than one with factory A/C....I'm sure this is one reason why my truck has a tendency to run hotter with the A/C on while towing. I think it's square vs. short and wider. 7. Ramming in cooler outside air is better than sucking it in from under the hood. Makes sense to me, the new trucks have intercoolers to cool the incoming air
Well, I hope this post helps someone and saves them the hassles I had,my truck is ok now. If anyone has any comments on the air dam, or ram air I'd like to here from you. Thanks to all, glad to have this website and all you great folks. Mike

 

Here I am on the way to work.



The air dam would not be a good option for me.

But I do have ram air that I really like.

 

Dave,

Did that custom air intake require a lot of cutting?.

It looks like you had to modify the driver side rad support bracket. I am looking to bring fresh air to my 93 Turbo which currently pulls in warm engine air thru the K&N turbo filter I put directly onto the Turbo Inlet housing. I don't feel like moving the antifreeze and windshield wiper reservoir so what you did is probably the cleanest solution short of going thru the hood with a hood scope to get fresh air.

 

I removed the stock bracket from the radiator to the radiator shell.
I also trimmed the front and back flange off the radiator side for 10 inches where the scoop goes in.
I made a new bracket out of 1/4" x 1" bar stock to support the radiator on the top.
I have all the sheet metal tools for HVAC duct work.
Took me about 4 hours to fab up the scoop and inside ducting.

Front is 4" x 10"
Reduces to 3" x 9" through the radiator shell custom made out of furnace plenum, the first two parts are one piece of metal

Transition to 6" round custom made out of 1' x 6" round duct
6" x 4" reducer HVAC part
4" adjustable ell HVAC part
stock 4" round plastic intake tube into the air box slides over the ell stock on 86 truck intake snorkel to air cleaner
I like it, I think it works better than a hood scoop would unless it was very tall or right at the front of the hood.

 

Thanks Dave,

I agree with you on the hood scoop. It attracts to much attention and probably would reduce the value of the truck.

What is the filter type and number you are running in your ATS Turbo inlet Housing? (I read somewhere you were using a Purolator?)

 

Purolator A44853 is the air filter for a 93 94 7.3 turbo in the book.
Advance Auto has them for 19.98 plus tax.

Since I installed the air duct I change it every 6,000 miles or less.
Lots of bugs in the summer, lots of dust year round in the excavation business.

I have got to get a screen over the front of it though, those Cummins 5.9's and Hemi's are hard to clean out of the air box. They splatter everywhere and are so gooey. Ucky....