I'm new to the board. i have a 1996 2500 2wd 12 valve with 130k and no mods. lately in the hot chicago weather, the temp gauge will climb to 230 ( red mark) w/o A/C on, after driving 25 miles. it will climb considerly faster with A/C on.

1) so far i've cleaned the outside of the radiator with the hose
2)checked air flow thru grill. holds a piece of paper to the grill
3)no coolant leaks that i can see. level never drops in the overflow
4)tested and replaced radiator cap
5)there is white smoke present on start up since i bought the truck last year with 108K
6) i replaced the t/stat with a cummins brand unit from the dealer earlier this year before the problem happened because the heat was poor and the temp never went much above the 140 mark on the gauge. didn't real fix the problem though.


i towed with the truck last summer with the a/c on and it never was a problem?

I NEED HELP! -Dan

 

White smoke just on start up? Could be coolant seaping around the head gasket. First thing. Check your oil. If the oil is greyish and higher than normal that is a sign that you have coolant in your oil. Second, Take your radiator cap off and have your truck running till it gets warm enough that your thermostat opens. Check in the radiator spout for presence of air bubbles or low coolant. Third, look in your coolant overflow for dirty, muddy looking coolant. All of these are a classic example of bad head gasket and would cause a truck to overheat. Hope this info helps, just speaking from experience and if I'm forgetting anything, anyone, feel free to critique my suggestions.

 

it may be the wrong temp themostat, spring to tight, or it may be in backwards?

 

prolly fan clutch if it is not head gasket

 

it's only happened when the ambient temp was in the 90's for 2 days, if that helps. t/stat is flowing. and fan pulls air.

 

sounds like a stopped up radiator to me something is not flowing

 

I agree, check to see if there is any oil in your radiator.I there is it is your head gasket.this happenened on my friends 6.9