Overheating 7.3L Ford F-350

[Gene Arnold]

My brother-in-law has a 1989 Ford F-350 with a 7. 3L diesel, automatic transmission, and Turbocharger. On his last pull it overheated and boiled as he pulled his trailer (6000 lbs loaded) up an access driveway. He says it overheats when he slows down or pulls up a grade, although, except for the above incident, he never boils away any coolant. He’s had the radiator cleaned and a new fan clutch installed not too long ago. After his last pull he installed a new thermostat (hasn’t pulled since then). He’s in Colorado and I’m in Boise so I haven’t looked at it but told him I’d find out what I could from the helpful TDR people.



Pertinent summary and questions:



1. I think there’s a strong possibility that no matter he has a newer fan clutch, he may need a new one. Other than listening for it to engage, is there a way to test?



2. He says the temperature gauge fluctuates. Are Fords similar to our Cumminses in that the fluctuation seems normal in ours as the thermostat opens and closes?



3. He recently had a mechanic set the timing. I suspect it may have been erroneous. What is the correct setting for his 7. 3?



4. There’s the possibility of a cracked head or a bad head-gasket. How do you test for this?



5. Possible collapsing lower radiator hose??



Thanks much!

 

[bmoeller]

Originally posted by Gene Arnold



Pertinent summary and questions:



1. I think there’s a strong possibility that no matter he has a newer fan clutch, he may need a new one. Other than listening for it to engage, is there a way to test?



2. He says the temperature gauge fluctuates. Are Fords similar to our Cumminses in that the fluctuation seems normal in ours as the thermostat opens and closes?



3. He recently had a mechanic set the timing. I suspect it may have been erroneous. What is the correct setting for his 7. 3?



4. There’s the possibility of a cracked head or a bad head-gasket. How do you test for this?



5. Possible collapsing lower radiator hose??



Thanks much!

1. Ask him if he hears it in the morning (or when cold) to listen for the fan running until the clutch warms up to disengage. He may need to cleant he fins on the radiator, or take it to a shop to have it cleaned internally. Was he given the correct fan clutch? Belt(s) tight?



2. Replace sending unit first. They should be steady on those trucks. May have gotten a bad thermostat.



3. Not sure what is set at, needs to be done dynamically (running), not static (off).



4. Yes, check for bubbles in the coolant with cap off. External leaks? Water and oil mixing? If so, is it engine oil or transmission fluid from the transmission cooler built into the radiator?



Another way would be a compression check (assuming the valves are sealing good). Can be done by pulling the fuel injection nozzles or a different adapter that is screwed into the glow plug hole.



5. Possible, but not likely. It should have a "coil spring" inside of it.





Has he been adding the coolant additive (FW-16 or DCA-4) to the coolant like he is supposed to prevent cavitation? How is his water pump?

 

[Shooter]

Check for cavitation errosion perforation of #8 cy wall, that is the most common problem , especially with it puking coolant while decellerating with no heat being generated. related to #4





Gotta love the PSD



#2 Contrary to some beliefs the temp on psd's and ctd's do fluctuate and are duley indicated on the temp gauge.



#4 If he does not know how to do it he probably will want a good local diesel shop to do it.

 

[bmoeller]

Originally posted by Shooter



Gotta love the PSD



#2 Contrary to some beliefs the temp on psd's and ctd's do fluctuate and are duley indicated on the temp gauge.

It's a '89, not a PSD.



I have a 6. 9L and my uncle has 2- 7. 3L N/A IDI. One is a '91 F-250 and the other is a '92 F-250. All 3 are rock steady as far as coolant temps, meaning not fluctuating like the Cummins does. My grandpa's '97 PSD was steady also.

 

[Scot]

There is an index line on the injector pump and the housing it bolts to. They are aligned when timed stock. It was suggested to me that it be advanced about "the thickness of a dime. "



My 6. 9 would use about a gallon of coolant every 300 miles after it got cavitation erosion.