Hello, new here, just bought a 97 960 wagon with a supposed blown head gasket. I am trying to be sure that is the problem. Thermostat had no gasket and the top loop was broken, new one ordered.
I am wondering about the circulation system after looking at the thermostat. Does the lower part open when cold and the coolant circulates in the block/head until warm? Then the lower part closes and the upper opens to allow coolant flow through the radiator? Very sophisticated thermostat looking thing.
I have no coolant in the pan, no coolant shot out of any cylinders when the plugs were out[new plugs ordered] and the car ran good whrn I drove it home[a short distance] didn't seem to have a miss. Since I am not sure about the circulation system, I was going to wait until the new thermostat gets here before I run it again. I left the cap off when I drove it home so it wouldn't build excessive pressure for the short drive.
From what I have read so far it appears there is no special way to fill the cooling system? And no bleed valves to purge air from the system? It looks like it should have one, the tank being the same level as the up and down hoses[heater etc.]
Thanks for any information, hope I get lucky. this car is in VERY good condition.

 

Thermostats for this car are very simple devices -- they let coolant thru at certain setting (185 F IIRC).

Coolant system is filled thru the reservoir. No bleed valves either. If you think you have air in the system (never happened in mine, although I have had it open many times), try to squeeze the top radiator hose.

Do you see oil residue on the coolant at the Reservoir? Best way to test HG is to do a leak-down test.

 

Got the new thermostat, seal and spark plugs today. It's a little over 100' here today. Installed new parts, bled heater core filled system, drove the car about 10 min. with ac on, had it parked idling with ac on. No overheating. Parked it shut it off, noticed a little liquid about the left front of the transmission. Seems to have a few drops coming from the lower heater core hose. It does stop, not continuous. 4 hours later, still pressure in the system, not completely cooled down yet, did I say it was hot here?
I am thinking no head gasket problem, I will have it leak down tested to be sure. Did you guys say the heater hoses were 5/8ths, I might just get a small u hose and by pass the core for the moment, while I sort it completely out. Who needs heat at 100+?

 

Heater core leaks inside the cabin. Your footwell carpet would be wet and strong smell of coolant inside the cabin.

On the other hand, Heater valves are notorious for leaks. They leak where you describe, i.e. left front of transm. Worse, they leak right over transmission's electrical connectors.

If you bypass the heater core, I would bypass the Heater Valve too. In fact I would get a new one.

Yes, heater hose are 5/8". Use a 1/2" copper pipe as a union. Last thing, I would get all new worm-clamps. Don't try to re-use. Not worth the aggravation.