I'm hoping you guys can lead me in the right direction. I have an '03 V6 auto with 90k and it about pegged the temp gage on the way home. I turned the heat on high, pulled over and popped the hood. The reservoir sounded "bubbly" and there was fluid leaking from the lower hose connection on the radiator (from the pressure, not a leak). So I let it cool off, checked the fan fuse, and made sure the fan turned on (it did). I drove it the last mile home and it was getting hot again even though I was doing 40mph the whole way with no stops and the heat didn't blow hot anymore. So I'm thinking maybe it was just low on fluid? There's always been coolant in the overflow tank, though. Could it still be low even with fluid there? Would a stuck-closed thermostat cause the heat to not work? What coolant do you recommend? The owner's manual wants you to use Chrysler ethylene-glycol but I think any E-G coolant will work right?

Thanks!

Check for leaks via pressure test,most likely a cracked radiator(upper corner closest to battery,plastic side tank) or a leaking waterpump/broken water pump impeller.

Yes the low coolant level caused the no heat,you had a air pocket in the system.


Use only HOAT coolant,found at any Chrysler dealer,Ford dealer,or Napa(as Zerex GO5).Do not use any other coolant,problems will occur.

Can you use a standard pressure tester since there's no traditional radiator cap? I pulled the serpentine belt off and the water pump spins freely (no fluid in the way)... doesn't feel like a broken impeller.

Well I drained what was left of the coolant and then pulled the water pump off. Everything looked fine except you could see a little coolant was seeping past the seal. So I put it back on with some RTV. Then I went to pull the lower hose off the radiator and the clamp snapped when I squeezed it. I guess it just got rusty enough to allow the hose to leak slowly. So tomorrow I'll get some new clamps and coolant and see what happens.

FYI tjkj called a broken impeller on www.jeepkj.com with another user that had a mysterious overheating problem. I didn't think a pump would have a broken impeller without noise, but this guy pulled his waterpump and found just that.

If you can't find anything else, pull the pump (get a new gasket because they are one time use) and inspect the pump.

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