my radiator has been leaking very little for some time and it is stock after 250k so im sure it is plugged....my engine has been running 202 .....imma replace it soon and im sure that will help...my tranny only goes over 200 while towing...otherwise if is under 190

 

That's quite an assumption you make; one which I would bet my bank account is wrong. If your radiator is plugged your truck will overheat due to the lack of flow. If you can tow a trailer without blowing your engine up your radiator isn't plugged. It's the thermostat that controls engine temp, not the radiator. One of the trucks that came to the OH meet was a 2000 V10 with a 200° thermostat. Like yours it ran right around 202°, but that had nothing to do with a radiator obstruction.

If you want it to run cooler get a 185° thermostat. It takes ten minutes to install and about $10. Your problem isn't the radiator.

 

My truck never before went over 197 and my tranny never went over 190 before this summer and the engine usually ran 193 and the tranny 170ish...but this year the engine STAYS at 202 empty the tranny 180ish ...and my radiator leakes approx 16 ozs of coolant per 500 miles .... you dont think it is the radiator?

 

Nope, I don't. The leak is a red herring, it has nothing to do with an obstruction or radiator performance in general. I had a thermostat fail in my Excursion a few months before I sold it. Instead of holding 184-190° it wouldn't exceed 180° under any circumstances, and sometimes got as cool as 168° coming down a grade.

$10 and 10 minutes of my time later, the engine holds a toasty 185-190° without any issues. Of course yours is running hotter than usual, but the same thing can happen. Unless the thermostat is wide open the radiator isn't the limiting factor in your cooling ability. So if the thermostat was wide open all the time and you were holding 202° then you may be right. But that's just about impossible to happen during real-world driving.

 

so your saying the thermostat effects my trans temp also?

 

It affects your transmission temp every bit as much as a radiator blockage does.

 

at idle my truck can hold mid 190s but the second i get on the gas......even cruising at 20...it holds 202

 

My brand-new F150 can fluctuate as much as 20° during regular operation. Coasting down a hill I'm as little as 183°, and coming up the other side I'm as high as 205°. Going from mid 190's to 202° is hardly indicative of a problem. Now if it is consistently running hotter, like if it used to run mid 180°'s then you need a new thermostat.

 

thanks Crazy...it just has never ran this hot before constantly....but is does have 250k now lol

 

i'm going to replace the thermostat and go from there...i live in Texas so imma go with a 185 one

 

Yeah, I believe it. My Excursion needed a thermostat at 118,000 miles, but I think time and coolant condition affect them much more than mileage. :-confused

 

i flushed my system approx 50k ago...maybe it is time again

 

Sounds like it, if I remember right the interval for my '00 Excursion was every 30,000 miles. I'm splitting this off from the OP's thread, I think we've derailed it enough!

 

You are right....imma flush it and sorry for the derailment lol

 

Hotpocket, had similar issues in my 05 5.4 at 225,000 miles, changed the thermostat and the issue went away. Simple, cheap and easy fix.