Overheating Issue

[erikwink6]

Hi guys I was wondering if you would have some insight into an issue I am facing with my 1500 Silverado Crew Cab 4wd 5.3L. The other day I was moving and I was towing a trailer with probably 4000lbs I would estimate. It was 105 outside and going down the highway at about 70mph my truck started to get pretty hot at probably 235. I turned my heater on as well as slowed down and I was able to finish off the day. I just figured that it was a hot day and I was pushing hard and didn't think much of it. No problems since until a day ago where I was hauling a fridge and some other stuff in the back on the highway and I began to overheat again. Same thing as last time but what is concerning me is that I wasn't moving that much weight this time and I began to overheat again. It was another hot 105 degree day and I am not sure whether its just because its hot out or something is wrong. Coolant is topped off, and my radiator looks like it could use a cleaning but it doesn't look all that dirty. Also I only overheated on the highway, slowing down driving in town was fine and even idling was fine, it was only highway speeds. Anybody got any ideas?

 

TLDR:

Truck is overheating at highway speeds only and only when towing at least a couple hundred pounds of weight. Idling and driving in town is fine.

[diyer2]

Has the cooling system been drained, flushed and refilled? Clean the radiator. Thats where  I would start. 

[erikwink6]

Less than a year ago it was. Yeah that’s what I’m currently planning to do.

[erikwink6]

Forgot about this thread. I ended up taking out my grille and deep cleaning my radiator, transmission radiator, and condenser. It seems to have helped greatly with heat. I haven’t towing anything that heavy for that long as of recently but it seems to have at least helped if not fixed the problem. I had a bunch of bent fins so I fixed that and installed a bug screen inside the grille to protect it in the future. Thanks!

[EightTrackHits]

I had a similar issue years ago on an S10 Blazer.  Lots of dead plant debris had made it up between the condenser and radiator and I couldn't see it without taking off the condenser.

[Z45]

https://cartreatments.com/clogged-radiator-symptoms-and-replacement-cost/

 

[Dan1]

I would make sure cooling fans are running on low and high speeds. Also, I think stye should kick on high when the AC is on.