My truck has had an ongoing cooling issue for quite some time. It would only over heat while towing on the highway. A few weeks ago I changed the thermostat which I found had only opening 1/3 of the way and figured I had found the problem. After putting the trailer on it the other night to haul it out of storage and the air temps in the 80's with the A/C on it would run hot going up a grade with the only real difference being that the truck would cool back off when going down, hill unlike before I changed the t-stat.

The trailer is only around the 5000lb area so the truck is not over loaded. The t-stat was tested in boiling water and is known to work. Also, the coolant has been changed as well as the degaus tank, cap and hoses. The area between the radiator and the a/c condenser free of debris. The water pump appears to be newer to the truck and I would suspect is functioning fine.

I'm starting to think that I might need to pull the radiator and clean or replace, it appears to be original and I'm not sure what else would cause this.

What are your thoughts on this?

 

How hot is it actually getting? What's the engine oil temp?

 

Not really sure, it only has just the dash gauges. I had the temp up just under the red 'zone' by 1/8 inch but never ran it in the red zone. Hope this helps.

 

The Charge Air Cooler (Inner-Cooler) is behind the A/C Condenser. You have to remove the Black "Tool Tray" to see behind the CAC and the front of the Radiator. They line up like this: ACC / CAC / Trans Cooler / Radiator

I'm just going to throw out some things her for thought in diagnosing this.

1. Are you using an OEM T-Stat? If not, I would consider it strongly.

2. When was the last time a COMPLETE flush of the system was done? I don't see a year on you signature line or description. Have you monitored SCA's if required?

3. You can remove the ECT Sensor on the Water Pump (which is not used on our trucks on the Water Pump - often used for filtration), install a Barb Fitting and run a 3.8" Tube into the Degauss Bottle to see if its flowing good.

4. Do you have an IR Thermometer or Radiator Temperature Thermometer? If so get a reading on the Radiator / Degauss Bottle respectively.

You really need to know the EOT and ECT to know where to start and the probability of damaging the engine. And most important is the difference between the two during operation - Normal is 15 to 20. Anything over 20 is considered to be out of design specification and servicing the Oil Cooler is recommended.

These engines are cooling wonders. Overheating just doesn't occur unless there is a T-Stat, WP Failure, Oil Cooler Failure, or Radiator Failure.

The Dash Gauge is not an accurate way to determine temperature. The incremental measurement is too wide of a band. You can latterly go from 180* to 230* without the gauge sweeping.

Do you have access to AE or a Scan Gauge II? Either will allow monitoring of the circuits necessary to determine where to begin. While AE doesn't monitor in *F it does monitor in Volts and the SC II can be set up to monitor ECT *F and EOT *F.

I certainly would not Tow or put the engine in a condition where overheating could occur. That would be unforgiving to the O-Rings and seals.

 

I see now it's a 2002. My Bad!

 

Mine did that to me on my way to TN for the 2nd RRE. I had a bike rack on the front and thought that was it it. My gauge pegged on a hill so I stopped and put the bikes in the bed. No change on the next hill.
So i stopped and changed thermostats and the ECT sensor. No change. I said eff it and just took it easy and turned the chip to stock. I was out of the tall mountain pulls by then and limped to TN. The only logical solution then was a bad fan clutch so I next day aired a new Ford one and it fixed the problem.

 

Fan Clutch

 

could be a bad rad cap?

 

Here's a picture of what I was seeing after I pulled my trailer home, I opened the hood the next day and saw this. Why would it do that to my upper hose? I loosened the clamp up and it started to draw air in and the hose expanded back to its normal shape.






To those who have mentioned the fan clutch I agree, my clutch has been suspect for awhile, it has never locked up when the motor was hot. It only locks up first thing in the morning when I start it, so I have a new one that I have yet to install. I just wish I could rule out the radiator in the mean time

 

This is exactly like mine but I just changed my tank and cap about three weeks ago, unless it was a bad cap from the factory.

https://www.ford-trucks.com/forums/1...tor-hoses.html

 

Were you having the problem prior to changing the Cap?

Do you have you're old Cap?

For the $20 Bucks I'd try another OE Cap. Or just exchange the one you have from whomever you bought it from.

Please keep posting. Like I said, these things rarely have cooling issues, so my curiosity is elevated.

 

Yes, I was having problems before hand but not the collapsing hose issue. My tank came with a new cap but I ordered an OE one along with it that I can swap out.

My next thought is that the radiator needs to come out of the truck and be cleaned inside and out but I have yet to find a reputable shop in my area to do that work so I'll keep looking.

 

Found a shop about 10 miles away that can do a flow test on the radiator so I think I'll be pulling it out and having it tested. Maybe that will reveal some clues.

 

I'm wondering if it's building up pressure when it gets hot and then when it cools down it is collapsing the hose and the cap can't release enough of the vacuum? Or does it do that with the engine running?

 

I'm not sure if it is doing that while running but after I opened up the hose clamp it drew in air. I'm hoping that having the radiator tested will reveal something.