Radiator issues still overheating

well, i got my new thermostat installed, seemed to stop the overheating but on long trips 30 pus miles it'll start running hot, now i'd like to note beforehand i have no fan shroud, if one is needed or a mix of 50/50 is needed for these trucks to run right i'd like to know ahead of time lol not very sure, i know some vehicles require a 50/50 mixture in the antifreeze to run right. But i had flushed the radiator when i changed my thermostat, water came out fine no gulping or anything nice steady stream from top and bottom hoses , after refilling with mostly water, i had a 3/4 jug of 50/50 mix and put in and rest water, i have good pressure on the hoses to my water pump and thermostat, waterpump has no noise coming from it and seems to be running just fine, but i again will overheat after 30 so miles highway, and even quicker in towns, so i'm thinking the radiator is busted or going bad, or i need a 50/50 mixture? but i'm getting or going to fabricate myself a fanshroud soon, but any help tips much appreciated.

Also, when overheating i'll stop and release the steam release switch on my radiator cap, it will hiss and puff steam ( nothing in my oil or indications pointing to my head blowing or being warped ) from the resorvoir, sometimes a little water, and the radiator will gurgle and bubble, just kinda lost here lol

If you overheat at highway speeds, chances are your radiator needs to be replaced.

Well I found a radiator shop nearby that tests them for 10$, and at most a 70$ repair fee, no idea on service time but hey better than the 134$ quote from advance and autozone, no o'reilly or napa nearby here.

That's also my thoughts. Instead of paying for a test and a repair, I strongly recommend (notice the capital letters) a brand-new 2-row radiator as used on the automatic models. That sure zapped my high engine temperatures a few years ago (in Arizona heat/climate too). I wouldn't throw any $$$ into an old radiator. And yes, you need a fan shroud.


A 50/50 mix itself won't affect things worth beans, but it is important to bleed out all air out of the cooling system (like jacking up the front end, running with radiator cap off to bleed out the air).

As said just buy a NEW radiator.I run the normal green and straight dilution.Fill system with at least one gallon of coolant and then add distilled water(this is better).Next heat on,fan on high setting,and place cardboard in front of the radiator(cut to fit) speeds the heating process.Let the truck idle,radiator cap OFF and some shop towels(paper easier to throw away) .Let idle for 15-20 minutes and once the coolant starts to bubble a lot out of the rad fill neck cap it.I normally add straight coolant to the overflow tank to just above the add line,then later adjust to about the middle once done.This to me is the most effective way and yes I do not use the 50/50. I do buy the walmart super tech coolant(blue jug of normal green) and add this 1st! then add distilled water 2nd for a higher coolant ratio over water.These b trucks hold about 1.5 gallons (on recall I think) and mix for my choice like -25 or so in nc and yeah not necessary but good high temp like 250 or above.If your heater core is stock you might want to consider replacing it (I did mine in 2010) and a difference it did make!I have done my rad,wp,htr core all together.I also use the ventlever radiator cap as well.