I have a 2002 f150 supercrew 4x4. It has the original 5.4 v8 and automatic with 307000 miles with no issues. I recently put a new radiator in it due to sitting in traffic it would start to run hot. Now I have no issues with cooling at all except I drove down to Florida the other day pulling my motorcycles on a trailer and during the 75 mph 400 mile trip my truck overheated. When I cut the a/c off it was fine and I didn't have any cooling issues at all. Can someone tell me why my truck over heats pulling a trailer with the air on but no other time regardless if a/c is running or not. Only when pulling. Thanks

 

Ever change your water pump? Is the system staying pressurized? Did it overheat at highway speed or idle? I assume you still have the mechanical fan and not e-fans. Lastly are you good on your coolant levels w/ no leaks?

 

Never changed water pump. It over heated at hwy speeds not idle and I still have factory fan. And system stays pressurized with water level staying the same with no leaks

 

When I backed down to about 55 the heat hand went down some but was still a lil warm but without the overheating issue

 

Check your radiator for debris and the fins for being bent. Could be a simple air flow issue.

I did a friend's BroncoII, it looked like someone was plucking chickens on the lower third of the radiator......new stat,flush,straightened the fins, and washed out all the debris and problem solved.

 

Just replaced with a brand new radiator a few days prior to my trip

 

Well..........I guess that aint it then!

Are you sure you got all the air out of the system?

 

I hope so lol. When I take the cap off it is flowing nice with no bubbles

 

The impellors on the water pump could be deteriorated, causing it not to circulate efficiantly.

 

Ok so maybe its time for a new water pump and maybe a thermostat since I've replaced the radiator.

 

How about the clutch fan to since I'm going to be replacing the waterpump

 

Pulling puts more stress on everything, thus creating more heat. With the truck warmed up turn off the engine with the hood up. The clutch fan should almost instantly stop turning <2 seconds. If it continues to spin then you have a weak or bad fan clutch. It maybe just strong enough that unloaded it can keep up with the demand of your right foot. Thermostat stuck open/closed would cause it to overheat loaded or unloaded. Waterpump also could be bad if the impeller is junk. I dont know on yours if its metal or plastic but either way at 300k miles its probably not in good shape.

 

Thanks ill check that out

 

When your truck is pulling a trailer regardless of size, it is producing more horsepower to do so and needs additional cooling. Combine that with 75mph speeds that require more hp and it isn't that surprising that it runs a little hotter. But, I suspect that a healthy stock F150 would not over heat. Maybe you do need a new water pump or maybe the engine has some crud in the cooling passages or it needs the 7700 gvw radiator.

I bought a new 2000 F150SCAB4x4. Ford evidently advertised the towing package had additional engine cooling but it in fact had the same radiator as the non-tow package trucks. There were enough complaints about false advertising that Ford offered all new owners the option of $100, a larger radiator installed (the 7700gvw radiator. I believe the stock tow rating was 6500lbs gvw), or $500 credit on a trade for a new truck. I chose the larger radiator but never needed it. Eventually, I started getting a CE code indicating the engine was warming up too slowly while working in Wisconsin in the winter. I dropped a large piece of card board between the radiator and the condenser to help it heat up faster and didn't get that CE code any more. But, that larger radiator may be an option. I sold that truck to a guy living in the UP and he bought a bra to put on the truck in the winter.