1986 Subaru GL Overheating
Remove the thermostat and go for a test run-see what happens- also make sure you bleed the system
Suggested Repair
Remove the thermostat, thoroughly bleed the cooling system, and test-drive to see whether the temperature stays down. If it still runs hot, further diagnosis is needed.
Conversation Summary
The owner of a 1986 Subaru GL Wagon reports the temperature rising after about 20 minutes, especially on hills or in traffic, while the heater lowers it somewhat. The fan works, coolant level is good, the system was flushed, the thermostat was replaced, and a blown upper radiator hose was replaced. Gurgling was heard under the dash. An expert advised removing the thermostat for a test run and bleeding the cooling system. Another user suggested a developing head gasket or cylinder-head leak could put exhaust pressure and heat into the coolant without immediate severe overheating.
