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While on a roadtrip, the car started overheating with coolant boiling out. We refilled the radiator with coolant, but it kept occurring. We managed to make it back home by having the heater on high with the fans on high and the windows open.

  • Radiator fans turn on, but it's blowing cold air. The lower radiator hose is cold. The top hose is hot.
  • The pump is circulating coolant for the cabin heat, so I think that should be ok.
  • Replaced the thermostat, but that didn't help.
  • No smoke out the tailpipe, so hopefully head gasket is OK.

Currently I'm trying to burp air out of the cooling system by parking on a hill, squeezing the hoses, and adding coolant. While draining the coolant to replace the thermostat, I was able to speed the process up by blowing air through the radiator cap, so it doesn't seem like there's a blockage.

I'm thinking the only things it could be is either the pump (but the heat works fine?) or the radiator (but there's no coolant leaking and no block?)

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Also, there's a squealing that started recently that goes away after the car has been on for a few seconds. – Jeff Lamb Oct 11 '12 at 23:06
I can squeeze the upper hose while the engine is running, indicating a lack of pressure. This makes me think the water pump isn't working. I don't understand why the cabin heat is still working, though. – Jeff Lamb Oct 11 '12 at 23:18
Any signs of oil and water mixing? – Timo Geusch Oct 11 '12 at 23:38
None that I can see. – Jeff Lamb Oct 12 '12 at 3:23
What type and vintage is the coolant? Any sign of sludge? – Mark Johnson Oct 12 '12 at 3:56
up vote 1 down vote accepted

Ended up being a cracked radiator caused by blown headgasket. This was verified from pressure tests done at two different shops. Repair quotes at $3300 and $3500. We ended up trading it in for a new vehicle, as at 197,000 miles the price to repair was coming close to the cost of the vehicle.

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