I agree there is great advice all over this site, but I'm just worried you may blow a head before it's figured out. I think the fact that you put stop leak in there clogged something up whether it's the radiator, a coolant passage in the engine, the thermo, I don't know. Have you replaced the thermo yet to see if it's intermittently sticking?

 

ok.....my bad..... i jumped the gun on the
hwy overheating yesterday.
I was low on coolant!
that explains yesterday so i'm back
to a clogged rad.
Sometimes things get you so nutz that you
lose sight of the obvious.
running cool and calm on the hwy.
KS

 

did you forget to add coolant after you "burped" it?
so, you've changed thermo and fan clutch? im not sure but you can get a flow test if you dont want to change out your radiator but to me a new radiator is only like 120 bucks and replacing it every 10 years isnt a bad option. if you change the radiator and you still overheat, then you probably need to seek a professional shops advice. good luck and keep us posted!

 

X2. The only thing that fixed my overheating on hills was a new rad and thermastat. I tried a different fan clutch (had a spare), increasing the collant to water ratio..etc.

If it were the fan clutch I would expect overheating at idle as well.

 

Funny.........I think I've found the temperature threshold for my clogged rad.
Filled it this morning without incident 40 miles to work....92 degrees.

Leaving work......117 118 degrees outside...............started running hot 30 miles in, so I blasted the heat and kept the overheating at bay.
Good thing it's not 118 everyday!

KS

 

BTW, that "stop leak" powder can do more harm than good, but sometimes there's no other choice. I worked on a Honda CR-V once that would only blow heat on the passenger side. Turned out they put in a bunch of stop leak powder and clogged up part of the heater core. Also, you don't have to buy the powder, ground black pepper works just as good!