I have a 1994 F-350 7.3L IDI turbo with 180K miles on it. I have been experiancing alot of overheating trouble when I'm pulling my 7000# camper up grades.

After about 3-4 miles at a 6% (or so) it was overheating. The radiator is new when I bought it and was confirmed by a diffrent Ford dealer. I changed the thermostate and radiator cap and still overheated.

I tested my fan clutch by manufacturing two brackets to lock up the cluch and that seemed to fix it, stayed cool on the hardest hill on the test drive. I choked then bought a new cluch and that made no diffrence.

The Ford dealer said that the injector pump wasn't working right and that that would cause the OH problem. So I changed the pump and installed new injectors, had the shop time it and it's ALOT better but it still got hot the point the overheat light was about to come on 4 mile 6% grade with my camper.

Question: Since I have changed everything and it ran cool when I locked up my fan clutch, should I look into airflow more? Should I replace my stock fan with a high capacity electric? or use one as a booster fan?

Any advice is appreciated.

 

I d check the thermostat or put a new one in it took me five 3 from napa and two from ford before i got one in my truck to work properaly. make sure its a theremosts from ford or international and test it before ya put it in. to test compress open stick a feeler gague in then take a sauce pan while the signfigant other isnt looking and fill it with water set it on the stove hang the theremostat by the feeler gauge off the side of the pot if ya will and start heating. while its heating put a thermomter in and when the thermostat falls off the feeler gauge look at the temp on the thermoter it should be very close to what the thermostat has stamped on it.

 

i would try thermostat as well. also check the radiator to see if coolant is circulating in it. If you have a heat gun use that to check temps at top and bottom of radiator. should be around same temperature. ive seen "brand new" radiators clogged and not allow coolant to flow through it.

 

make sure you have the fan shroud installed if you do not allready have one.it helps

 

I run a 180* stat instead of the 195* they try to sell you at the parts house. I've run in over 100 degree heat with my camper and boat on... uphill.

 

What kind of outside temps are you in when it is overheating?

I would consider using the electric fan as a booster fan to help cooling. If you are pulling the grade at a low RPM (2000) you are probably making to much heat for the fan speed to pull enough air through the radiator. This will be even worse if it is warm and you are running the AC.

I would also consider adding a pyrometer to the exhaust manifold to see how hot you are getting the pistons and turbo. I just installed a remanufactured 7.3 IDI turbo in mine with a pyrometer. I am still amazed at how easy it is to get the exhaust temps to high for the pistons or turbo to live a very long life.

I can see exhaust temps as high as 1100 on a 6% grade in two miles with an empty truck at 70 MPH (2550 RPM). Pistons and turbos start to melt at 1250. With a high profile camper a headwind could get you that hot on level ground before you even knew it.

All turbo diesels should have a pyrometer installed. Turbos make lots of power, turbos also make lots of heat with the power.

 

Thanks for the help.


- I do have a shroud

- I put in 180 stat

- I don't have a Pyrometer, but planning on getting one soon

I'll replace the stat with one from a Ford dealer as you suggested, sounds like that's a real problem with these trucks.

I'll also see about mounting a booster far, If I remove thestock fan and use a electric sompletely, would there be a noticable power increase?

 

My stat is right from Napa, works fine. I did pull my radiator and blow all the dirt and muck out of the fins.

Do you hear your fan kick in when the temp rises? They sound like a howling dog.

 

Brimhall,
Yes you will notice a big gain in power and about 1.5 - 2 MPG increase. But....

I took the fan off my 86 6.9 for about two years.
It was a lot quiter, and had a lot more power.
It warmed up lots faster in the winter.
I usually did not even need to turn the electric fan on unless I was driving very slowly, plowing snow, pulling lots of weight uphill, or driving very fast. For some reason the radiator gets enough air to run 55 or 60 but when you start driving 70 or 75 on the interstate the air does not cool the engine. Probably has a lot to do with how high the truck sets with all the driveline hanging out in the air flow under the truck.

The problem was that, I never could find an electric fan that was able to last very long at all. I also could not find one that was able to handle the job alone, although NAPA did say they had one that should, but it was over 300 dollars for one.

I was running two 20" booster fans that did the job, for about six months. Then it was time to buy another one at 100 dollars each.

You must run a fan always when the AC is on, I ran both of mine if it was 80 or more outside.
Another downside is that the fans were elecrtically noisey. If I was in an area where the FM signal was not strong I could always hear the fans in the stereo. That probably could have been eliminated with the right capacitor value setup in the power feed.