Hauling heavy loads on 2005 1/2 ton

Scorpyd · May 22, 2018

Note: 2005 GMC 4.3 (electric fan) 1500

I have been using this truck daily to and from college, as a gas saver, and when I sit for maybe 5-10 minutes on a red light or maybe even a train, my truck’s temperature starts to rise. Stuck a colder 170 thermostat in place of a 195 thermostat. When ran the colder thermostat, the truck ran good for about a week or two and one day, the check engine light stayed on. That day, I was headed to a buddys on a mountain. While going up a mountain/incline, my truck’s rpms jumped and was able to get it to a flat spot, just before the rpms jumped rapidly and shutoff. Stayed in the 1500-2000 rpm range, as always. Dad towed the truck home and said it was the fuel pump. Changed the fuel pump out a few days later and the truck ran but acted like ran lean. Engine light was still on, took it to autozone and they said it was a engine coolant temperature sensor. It sounded right, we replaced it and my truck would not start but turned over. Stuck original ECTS back in and truck ran again. Took it to advanced, they said crank sensor. Changed that, truck ran good but the engine light was still on. I got the idea of putting a 195 back in, and did, and the light went off after heating up. Truck still over heats now while sitting at a long light or train. Truck runs at 195 always but goes to 210, 212, or higher when stopped for a bit. What can i do to help this out and run cooler? My dad has the same exact truck except his has the clutch fan and was made 2003 or 04. Both has 4.3s but his never over heats, even hauling weight

Supreme Pizza · May 22, 2018

If its overheating at stops, then you have an airflow problem. When your going 30+ MPH, you don't need a cooling fan at all. At a dead stop, your fan is paramount. Does your electric cooling fan come on when its overheating? Does the fan speed change at all? Try bleeding the cooling system. The thermostat is only one part of the cooling system to consider.

Edited May 22, 2018 by starman8tdc

Supreme Pizza · May 22, 2018

Donstar · May 22, 2018

Old 6 cylinder pickups were my college transporter of choice! I fondly remember relying on buddies or Dad to help keep my trucks running. I wish I had the internet! It sounds to me like you're getting a shopping cart full of suggestions. I believe Starma8tdc has focused in on the problem. Go to a shop that specializes in auto cooling (Radiator shop) and have them check out your truck. My first thoughts were water pump and/or blockage...