I have been pulling 5th wheel trailers for the last 6 years with no problems. Last year I upgraded to a new 27' that i thought would weigh less than my 84 24' King of the road. When I pulled my new 5th off the lot I knew that it was heavy so before I attempted our usual Summer vacation I chainged the rear end to a 4.56. This helped me pull the grades last summer. Last month we went out on a weekend trip, (mild grades) and I noticed an elevated temp. as I engaged OD and on some mild hills. I never overheated but prior to that my gauge never moved past 1/4. Last week we drove to Yosemite without my 5th and I had to stop midway up the grade because of high temp.
It runs all day at normal temp on flat lands but as soon as start climing my temp starts climing as well. I installed a new radiator because of a small leak but that has not helped. I run Amsoil in motor and trans and have had no trouble in 190,000 miles. Why am I overheating?

 

May as well go for the new thermostat, could be sticking. A good coolant flush would be in order too. Good luck, Rob.

 

Is the new trailer wider or taller than the old one? If so, increased air drag might be causing the engine to work harder and heat things up.

 

Could also be the water pump, through time the fins can erode and not push as much fluid as they should to circulate. (It is very rare but it happens) I agree with 7700Rob change the thermostat and flush the system. Also the question that must be asked is the fan engaging and cooling the system down. when they changed the radiator did the reinstall the fan stroud, if not or if any part of the fan shroud is missing it would also cause a problem.

Lance

 

I have ordered a new thermostat and water pump, I think I will replace both of them. Im close to 200,000 and these are the originals. The fan shroud was reinstalled correctly when the radiator was replaced.
My new trailer is taller and may be just a tad wider, but last year going up 8,000' my temp never exceeded 1/4 travel even at times of WFO with A/C on. I cannot say enough about the performance of this little truck, I sold my 84 F350 CC 460 in 97 and was sorry I did right from the start, I found my current F250 on a lot with 11,000 miles and I grabbed it. All I have had to do is replace one coil pack, radiator and battery. From the start I had the motor and trans flushed and filled with 100% syn. I flush my trans every other year and change the motor oil at 5,000. Thanks for your responses!

 

stupid question but did you check to make the gauge wasn't bad? Was the engine overheating or did the gauge or temp sensor go bad?

 

I haven't checked the gauge but I dont think that's the problem, I drove all the way from Fresno to the grapevine in 100+ heat with the air on at 80 mph and the temp gauge was normal (1/4 travel) as soon as I started climing I turned off the air and my temp gauge started climing, 400' from the summit I had to pull over before the gauge maxed out, I let it idle and opened the hood. The temp went back down quickly, there were no leaks and the degas tank showed level at normal (hot level). I just picked up my new water pump and thermostat and will install tonight. Saturday will be the test as we will be towing the 5th wheel up to Big Bear, I go up highway 38, its longer and the summit is over 8,000' but its a milder grade. I will let you all know what happens. Thanks for your advise!

 

good luck!!!! i hope it works out for you.

 

Yep, hope this works, let us know for sure!