I just picked up a very nice 1 owner 03 with 160k on the clock. it has the 2.3 and auto trans. the first time i got on it hard, about a mile or two from the house, i pulled in the driveway and noticed coolant leaking from under the truck. upon further inspection, it was coming from the passenger side upper hose where it goes into the radiator. I noticed someone has put an aftermarket screw style hose clamp on there. I added another clamp and it helped but it still leaks coolant when you get on it hard. the hose doesnt appear to be leaking and neither does the radiator. seems like the seal isnt good enough but its got two clamps on it! I replaced the reservoir cap and it didnt help. there is also a steady stream of coolant that runs into the tank from the overflow line and the flow increases with more throttle. is that normal?? im planning to take it to a friends shop on monday or tuesday to check for a blown head gasket, but anyone have any ideas of what it could be?? thanks!

 

is it possible the radiator outlet is cracked?

 

Is the temp gauge reading mid point when warmed up and staying there? If reading higher when pushing it there is a cause. The t stat is not replaceable separately but only as a unit with housing, temp sensor and electric heating element that opens it up. It could be stuck shut. Also water pump, electric cooling fan (in front of radiator) water pump and fan clutch and clogged radiator and head gasket as mentioned should be checked.

 

"Abnormal" pressure building up in the coolant system makes me think of a blown head gasket...

 

My coolant reservoir was leaking where hose attaches at bottom of tank.
I used a turkey baster to suck the coolant from reservoir,removed two screws,removed tank, used regular pliers to squeeze the spring clamp and replaced the original spring clamp with a small screw/band(wormgear) clamp.That is all contingent if that is where your leak is coming from. If
the upper hose to radiator is leaking at the radiator neck and hose looks good---this is what I have done in the past.If there is enough play in hose this is what to do. Purchase a S.S. screw/band(wormgear) clamp of correct size,unscrew the clamp so as to be able to place it around the hose,rescrew clamp around hose(loosely),unscrew old clamp and remove it from hose,take a sharp utility knife and circumscribe a cut 1/2" wide cut around hose(you'll have to make a perpendicular cut before you complete the cut around the hose to aide in removal),with a rag wipe some of the white crud where you removed hose(you'll probably get a little coolant dripping out at this time),then push the hose over the neck of radiator as far as it will go,place and tighten clamp.CAUTIONO THE ABOVE PROCEDURES WHEN ENGINE IS COMPLETLEY COOL.

 

I replaced the upper radiator hose with one from napa. its made from much thicker rubber. while i was changing it, a small piece of the nipple (where the hose attaches) broke off. I still put the hose on it, drove it and it seems to be much better. I'm hoping the problem will be fixed with the thicker hose and new radiator. still planning to check for a blown head gasket and go from there. thanks for all the input and suggestions so far!

 

It was the radiator. The nipple where the hose goes over had a pretty big crack in it not letting hose get a good seal. New radiator, hoses, and went ahead and did the thermostat while I had everything apart and all is well so far. Also had the coolant tested for hydrocarbons and none were found! Thanks for all the help!

 

Good to hear you got it going again! Sounds like these tanks crack in that area a lot.