Are all the radiators in your trucks the original? I have noticed in my radiator that it doesn't flow as well as it did when new. I flushed it and it still doesn't flow as well. I have towed a lot with my truck and when the radiator was new I had no cooling issues, now that it is old, it doesn't cool as well. Maybe just replacing the radiator and water pump would solve the problem. Any thoughts?

 

I think you made the best choice by going with the CSF all-aluminum radiator, which is a true bolt-in swap. It cools great for me. I'm using a good hi-flow 180 degree Stant thermostat and also made sure that I cleared the block of muck that tends to accumulate around the lower part of the cylinders by removing the block's freeze plugs. It's certainly an easy swap with fabrication or hassle required.

 

Change your thermostat, and while you're there, change the bypass hose. Could be the thermostat isn't opening like it should, restricting the flow.