Help! Truck is heating up trying to find problem!

[mah1964]

03 6.0 edge tuner and exhaust
Ive had this truck for the last 70k miles... it now has 160000
I believe it has had the so called "kettle whistle" since i bought with 90000
miles on it.
I have also had a heating up problem since i bought the truck under load.
If im pulling a trailer it will run 200-220 but not overheat and if im daily driving it runs from 180-195.
I have put on two new caps in the last year and had it pressure checked for head gaskets. Mechanic said no head gasket problem.
Is there something that will just make it overheat underload?
My brother just had his blow at 99000 miles.
Anything would be appreciated?


Has new egr valve and fan clutch... also flushed the coolant system with new coolant. I still drive this truck on a daily basis with no problems other than its a 6.0

[Ryan Rønning]

Its just running hot from the weight of towing. It sounds normal to me.

Hows your trans though, those edge tuners are famous for tearing up transmissions!

[mah1964]

I have had this problem ever since I got this truck but just wondering why the temp is heating up so much? Trans is starting to clunk a little but not bad. I tow probably 5000 to 10000 lbs a couple times a month

[Ryan Rønning]

Unfortunately I dont know much about the 6.0. The temps dont seem that high to me!

[briguy1982]

i run to different thermostats in mine a 175 in summer 195 in winter mine would do the same thing run about 205 210 empty 220 225 loaded only reason i switch back and forth is when it gets 20 below up here its no fun to drive around in a snow suit to stay warm

[CCdually6.0]

The Factory T-stat is the issue. It's a 'progressive' t-stat. Designed to open slightly at about 192F and not open fully till about 220F. I'm not a big fan of that thought process. Looks like the entire cooling system can become saturated while towing heavy loads. I replaced mine with a standard 192F and no more issues. The swap-out is easy and for about $20. Also a good time to do the zoodad. good luck