I agree with those gauges are only a suggestion. You need to get an Infrared thermometer, drive it until it is hot then stop and check the temp at the water neck and the top and bottom of the radiator. You may find your gauge is lying to you. I understand if you have AC and are in a lot of stop and go traffic you may need an electric fan but make sure it is a quality one made in the USA, and it moves a couple of thousand CFM. Some of the chineseium ones are junk and actually slow down the air thru the radiator.

 

Not running the ac when pulling. In fact,I get anxious when it’s over to the right ( almost to that last slash) I will run the heater and the needle will drop back to just above the middle). This is my 2nd rebuilt engine in it and I’m very anxious about it overheating to the point it cracks the block. I would think she could pull this trailer on flat surfaces without getting hot. This last time, the outside temp was barely 80 degrees.

my mechanic this past week, installed the 3G altenator with the built in regulator. I had to be towed this last time because she lost her altenator belt…really? I knew I was running on battery about 29 miles from home. Just had a new voltage regulator mounted below the dash, so I knew I was in trouble.
mechanic also, flushed the cooling system this past week. He still has the truck.

when not pulling the trailer, the truck runs like it just came off the show room floor but I basically am cruising around town in it, not on the highway. When I first got the truck, there was an aluminum dryer hose connected to the air filter and sat open at the front of the radiator which, I am assuming brought air into the engine compartment. It’s not on there now, should I put that back on?

 

Also, thinking of adding a separate transmission cooler in hopes that it would help. Aluminum radiator is about 3 years old with dual fans with built in shrouds….

 

You should dig out the receipts for your radiator and fans and post what it is. That way it will be easier to tell if it is large enough. The F250 Camper Special parts truck I have has a copper/brass 3 row, 19-1/2 X 26-1/2 core. They just had a 4-blade fan and no shroud and made their living doing just what you are doing with your truck.

 

I have to agree, I've experienced this in the past with a 160 thermostat. The cooling system has to work harder to maintain the lower temp, It's possible the coolant is circulating faster then the radiator can cool it. The cooling system is designed at bare minimum to maintain 180..

 

And to pile on, I've read warmer temps burn volatiles, keeping the oil cleaner and adding life to the engine. I put the stock 195 back in mine, from the 160 that was in there, and run just fine.

 

That’s what I will do when the truck comes home. I will pull all of my paperwork ( stored behind the seat) and post what that radiator is…I think it’s a 3 row, know it has two electric fans with shrouds on it…but don’t remember where I bought it from or the brand,
. It is aluminum. I really appreciate everything on this forum. Not giving up yet but still casually shopping for a used tow vehicle like a Chevy Tahoe or something.

 

Just a little bit of additional information I thought I'd add. Some of the 1965/67 F100/350 series with 352 and automatic transmission used a 5 blade fan. The ID markings on them are a little different but is noted in the master parts catalog. For 1966 there was even a 6 blade fan that was used with dealer installed A/C. I think @66v8baby is running one of those. Of course, it doesn't really matter in this case since the truck being discussed is using the electric fans.



912742 - this one with a date code of E66 or May 1966. My 1966 F250 Camper Special is a June '66 built truck so fairly late in the production year.



If it were my setup and it was overheating on me or climbing that high in temps compared to not towing, I wouldn't be opposed to running a separate cooler to take some of the demands off of the radiator. Not only can you either dedicate the radiator to just the engine or use the transmission cooler in it (assuming that's what you are doing) as a secondary cooler. If you run the transmission fluid either only or first through a dedicated cooler it can help extend the life of the transmission as well as not break down the ATF as quickly. Ideally you might want to avoid putting it in the path of the radiator. I'd look for a stacked plate design with a shorter profile and mount it below the radiator. Something like this as an example. Not suggesting this one, since I have not used it, just one that caught my eye as being a possibility.