I have run out of ideas..

I have a 19' Toy hauler, fully loaded I figure around 7200 pounds. When ever I climb any type of grade while towing, my trucks temperature starts to rise to just below 260. It would go higher but I stop and let the engine cool before going further.

I have flushed the cooling system, replaced the water pump, replaced the thermostat, replaced the radiator and hoses, added an external trans cooler, removed the stock fan and shroud and went with a dual electric variable speed fan with built in shroud. I also have checked the hose for water flow and seems fine.

I do have a 3" body lift and I run a 33" tire. The truck has 92k miles on it.

Any help would be appreciated!

 

you could install a toggle switch and turn fans on any time you want to. just go for really HD one, otherwise, it'll melt in no time.
do you have, by any chance, high temp thermostat installed?
is the CTS working properly?
is the fan on switch working? meaning - does the viscous clutch in the fan work right?
check serpentine belt. there's a gauge for this on the tensioner. is it still withing parameter?
there's Russian way of cooling down overheating cars, but I'd keep my mouse shut on this.

 

The fan is working properly.. It cycles at 60% speed and when the probe detects higher temp it runs at 100% speed. I can add a toggle to it just to be sure it is on.

I do not believe I have a high temp thermostat.. Would a high temp thermostat lower the operating temp?

I did replace the serpentine when I did the other changes.

Would an oil cooler help?

 

I was thinking on replacing my single core radiator with a dual core Silla radiator.. I figure this would double the cooling power.

Anyone have any comments?

 

What kind of thermosatat did you buy? Did it have a quality sticker that said made in china? Did the problem come after electric fans or before? I dont trust electric fans in my everyday vehicle!!! I would try a hyper tech powerstat cheap and suppose to make your vehicle run cooler. Also make sure your gauge is working right mine use to rise real high then one day it just quit working. Also make sure your oil does not look like chocolate milk this is never a good sign!!(blown head gasket)

 

Carefully hose and wash the dirt and mud out of the EXTERIOR fins of your radiator. You did a bang-up job of getting the internals clean. But without a clean exterior radiator surface the heat has nowhere to go. Mud and dirt act like a super-insulator(which is bad, in this case) trapping the heat in the system and moving coolant back to the engine hot . Cheap fix, no parts involved, takes 10 minutes.

 

Just curious what is the outside temperature your towing in? Id say if you have cleaned the rad inside and out and replaced the water pump ect. one last thing make sure your rad fins are not all bent closed.. If thats not the case then I would buy the bigger rad like you say. It would probably give you the best bang for your buck as far as cooling goes. Also Just an idea, in theroy you could install a system like a intercooler sprayer but have it mist your rad with water to add some evaprotive cooling but like i said thats just a quick idea and i dont know if it would be practical.

 

Many people don't realize the water is what transfers the heat most efficiently through the system. Point in case, most Nascar vehicles run with almost straight water.(Since the engine gets torn down after every race anyway.)

The antifreeze does just that, keeps the REAL coolant, (the water) from freezing in the wintertime, and boiling in the summertime.

Try to be sure the proportion of water/antifreeze is AT LEAST 50/50. In your case, you might want to try 60/40, or even 70/30.



Furthermore, the rubber sealing ring in the radiator cap develops a set, and dry-rots after a few years. Then your system's pressure goes to 0(normally @14PSI) at which point the coolant boils. Don't even test it, it costs 1/5 as much to replace it with a new one.

 

What type of Coolant are you using?

 

I see the problem a diffrent way you have a lift with larger tires the as this has changed the gear ratio so you are working the drivetrain,then pulling 7200lb,If you are seeing that kind of engine temps you could only imagine what kind of trans temps you are running,My opinion is gears,or sell it and get a diesel,sorry for the long post.