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xt6 cooling problems

Hi. I have a 1991 Subaru XT6 AWD auto trans vehicle. It experienced a bizarre problem yesterday where both the upper and lower radiator hoses bulged, as well as the overflow tank.

The overflow tank seemed to swell, like a balloon. The car also expelled a great deal of fluid and pressure through the hose going from the radiator to the oveflow tank. The antifreeze was in good condition, but it had been about 15 below zero for the past three days.

When the problem occured, I had been driving for a short period, the heater worked well and the temperature gauge was just barely off the c mark. Suddenly, about a block later, the guage went all the way up to H area, and I pulled into a parking lot, where just at that time the antifreeze was starting to spurt out under high pressure from the rubber hose that goes to overflow tank, as well as the overflow tank itself, which was swelling.

I drove home, all the while with the heater on high to try and bring the temperature down. Suddenly the car started blowing cold air out of the heater vents. At that very time I pulled into my garage, shut off the engine and saw there was still antifreeze being expelled under high pressure from the overflow hose and tank, and I also noticed the upper and lower radiator hoses were bulged. I checked the dipstick and was relieved to not see any water or milky chocolate color.

I let the car sit for about four hours and noticed the upper and lower radiator hoses had "imploded", just of the opposite of their bulged condition I had noted earlier. I removed the raditaor cap with great difficulty, as there was a vacuum in the system.

Any idea what happened and any damage that may have been done? I wonder if the thermostat failed and the result was the sudden and drastic buildup of pressure and heat I explained above.

I intend on changing the thermostat (any idea as to which temperature thermostat is best to use) and the upper and lower radiator hoses and then starting the car and see if things are ok.

Any help or suggestions you can provide would be appreciated.

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Reply to
st asia
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My guess based on your description of the puffed up radiator etc is either a cracked cylinder head or blown head gasket. All that excessive pressure had to come from somewhere.

Reply to
johninKY

Sounds like blown head gasket.

Reply to
CompUser

Could it have been caused by a stuck thermostat?

Reply to
st asia

The extra pressure could be from overheating. I had a Ford Contour with a water pump that had a plastic impeller. One day the impeller disintegrated and the water pump no longer functioned. The result was an overheated engine and coolant coming out of everywhere.

-R.

Reply to
Richard Chang

st asia wrote: (clip) I wonder

^^^^^^^^^^^^^^^^^^^^ I think you are on the right track. The most optimistic explanation is that the thermostat failed to open. This would cause the coolant in the engine block to boil, in about the length of time you describe, and, of course, bulge the hoses and cause fluids to blow out into the coolant reserve jar. If you caught it in time, replacing the thermostat will be both a diagnosis and a cure. It is possible that the overheating could have caused a blown head gasket. Seems to me that if you had a blown head gasket, air would have leaked in when it cooled, and you would not have had a vacuum later. You'll soon know. Good luck.

Reply to
l.lichtman

Richard, I think you are right.

This happened when it was 10 below zero outside, and had been that cold for at least thre successive days. I replaced the thermostat, and the radiator hoses, refilled with antifreeze and hoped. I chose the 192 degree thermostat (instead of the 180 degree unit) (hope that the 192 degree thermostat was the better choice).

After starting the engine, there was no evidence of problems. No moisture being emitted from the exhaust, no water contamination of the oil, no leaks, no overpressuring of the hoses, and the temperature was constant, just 1/4 of the way up the gauge. The heater also worked well.

I th> In article

Reply to
st asia

I am lucky. I changed the thermostat and there was no problem after that.

This happened when it was 10 below zero outside, and had been that cold for at least thre successive days. I replaced the thermostat, and the radiator hoses, refilled with antifreeze and hoped. I chose the 192 degree thermostat (instead of the 180 degree unit) (hope that the 192 degree thermostat was the better choice).

After starting the engine, there was no evidence of problems. No moisture being emitted from the exhaust, no water contamination of the oil, no leaks, no overpressuring of the hoses, and the temperature was constant, just 1/4 of the way up the gauge. The heater also worked well.

Now that everything is working ok, I still wonder if the thermostat temperate choice of 192 degrees (instead of 180) was the best choice.

Reply to
st asia

I wo nder if the ambient temperature wa a contributing factor? Antifreeze if not mixed correctly will "freeze" if the mixture is too weak or too strong. Any chance I could get you to visit/join

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Reply to
johninKY

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