What would cause a 1991 Chevy 1500 to overheat while towing camper

Question

Engine rebuilt 5k miles ago along with tranny. Overheats when towing camper trailer. What could cause it. Radiator? Heater Core? Thermostat?

Answer 1

Too much weight, dragging brakes either vehicle. Not enough coolant, cooling fan not working (clutch on fan not turning it fast enough.)

Not shifting to lower needed gear. Radiator needs flushing. Too much antifreeze. Transmission oil cooler not big enough or blocked.

ETC     ETC

Answer 2

Back then, Chevy tended to put two row, cheap radiators in the 1500s that were barely enough to cool the engine. A trailer or a steep hill always made them overheat. You just need to put a high quality three row radiator in there.

Answer 3

you need to make yourself a towing package, an external oil cooler, an external transmission cooler, and if you can get your hands on one, a 454 radiator with 4 coolant cores instead of 2.

Answer 4

when the engine was rebuilt it was probably bored .30 over. boring removes metal from the cylinders. the thinner the cylinder walls, the harder it is to cool. a bigger radiator and cooler thermostat will help. also have the timing checked by someone who knows what theyre doing. incorrect ignition timing can cause overheating. you might also consider an electric cooling fan, external trans cooler and bigger air filter. hope this helps.

Answer 5

sounds like you need a bigger radiator.

What size engine is in it  

Answer 6

pulling anything puts your truck in a greater strain thus producing more heat. Campers are  heavier than they appear and is probably at your trucks towing limits. also Yout transmission cooler is built in to your truck radiator adding even more heat into a max out radiator. The fix would be an external transmission cooler and a full coolant system flush and trans flush.

Answer 7

Not having enough horsepower and torque.