Wonderful

ok, so last night it snowed and got really cold here. I got up this morning and drove my jeep to the usual carpool spot and left it. Then this afternoon got off work and drove it home as usual, as i was getting off the freeway about 10 blocks from my house there was steam coming from under my hood and it smelled like antifreeze, I drove it home the temp did not go up at all. I got home and opened the hood and there's coolant everywhere. I start it up and i can see coolant coming from the lower radiator hose, it's old so i went and bought a new one, put it on nice and tight and its still leaking the i notice i have sprung a leak in my thermostat housing gasket as well. I have a bad feeling this is an issue with the water pump, any ideas?

btw, 89 engine 4.0l, recently rebuilt

Clean the crude out of the vent cap for the football, refill and burp it. Hope the seal isn't gone in the water pump or you didn't pop a seam in the radiator.
Check that your coolant mix tests to well below the anticipated temperature.
You may have had ice cubes in your coolant system, the cap stuck shut and wouldn't let it vent, the thermostat stuck shut, or the radiator clogged over the years from calcium.
You can soak the fill/surge tank cap in vinegar over night, make sure the vent moves. If the pressure got high enough it's likely your surge tank has cracked.

the radiator cap had a bunch of gunk stuck to it, kinda looked like grease or something. my surge tank is an old windshield wiper bottle with a rubber hose stuck into it from the radiator neck, it is sealed in there. I'm thinking your right about the thermostat frozen or sticking, it was probably 10 degrees here yesterday and i parked on a slight decline so it may have frozen, i always put the 50/50 coolant in my rig but i've never tested my coolant.besides the thermostat and the radiator, what could it be? water pump? its never had problems cooling or heating up.

Check the coolant anyway. It will probably get even colder someday soon. The water pump won't cause leaks in other areas, only at the water pump.

Actually, when I re-read your post, and the gunk on the radiator cap, I suppose you could have combustion pressure getting into the cooling system. If you run the motor with the cap off, do big bubbles of air show up in the radiator top?

winterbeater said:

Actually, when I re-read your post, and the gunk on the radiator cap, I suppose you could have combustion pressure getting into the cooling system. If you run the motor with the cap off, do big bubbles of air show up in the radiator top?

Click to expand...

x2...it does sound alot like a busted head gasket.

"recently rebuilt" with an old hose?