cooling system refill problem

[silvermike19]

hi everyone. i recently bought a 1993 eddie bauer explorer with 135,000 miles from a friend of mine. it's in great shape, but needed some maintenance work. i worked on the cooling system this weekend - drained the system, replaced the upper and lower hoses, and then flushed the system out. when i refilled the system with fresh water to make sure i got all the flush chemicals out of it, is where i ran into a problem...

started it up and let it warm up - with the radiator cap off and the heater on max. the gauge took a little while to do anything, but then quickly moved up to past halfway and slowly climbed toward out of the normal range. i shut it off right away because i didn't want it to overheat... you could hear the coolant in the upper hose boiling, and it was bubbling out of the top (since the cap was still not on). this happened twice in a row, so i took the thermostat out to let the water flow unrestricted... and of course it ran on the cool side... so there was no boiling issue.

i did buy a new thermostat (and gasket) to put in anyway, but didn't get to that step yet... does it sound like that old thermostat was stuck closed? it didn't seem to have a problem before... would messing with the cooling system do anything to it? anything else i should be on the lookout for?

Thanks!

-Mike

 

[ma96782]

Put the new t-stat in, fill it up w/ regular water (if you aren't confident) as a test. With the cap off........turn the motor on and watch.......as it heats up.......the water level will suddenly drop (t-stat is open).......now, watch for the "flow," through the radiator. Is the water colored, "brown" or "oily" or clear. When was the last time the cap was replaced or tested?? IF you can't remember........IMHO, a cap is cheap insurance. Cap it up, go for a short test drive it

IF everything seems good........cool off the system (never open when hot).........drain and replace w/the correct mix anti-freeze.

IF it doesn't work right.......try a pressure test of the system. Remember, the pressure test can't test the water pump or t-stat operation or the effeciency of the radiator, but it is good for leak testing.

Aloha, Mark