Bought a 90 legacy & discovered it had an overheating issue. Aftermarket temperature gauge (came with vehicle) reading 210 as operating temperature, but would drop to 170-190 at 50-60 mph.

 

Trouble shoot fans, both fan motors are dead.  Replaced both fans.  No change in temp. Curiously, the both fans run all the time, even at cold start up. 

 

Trouble shoot coolant, coolant is ok.

 

Trouble shoot thermostat, get OEM aftermarket brand supposedly designed to keep temp at 170.  Drained coolant and installed new thermostat, fillled with fresh coolant (but did not start at engine block..'burped' ...just filled into radiator) and temp now runs at 200. Will attempt to burp system today.

 

Is a fun car, but the cooling thing is really strange.  Any thoughts would be appreciated.

Edited March 24, 201313 yr by andygraham

good job on the t'stat but, wonder if the prev. owner has monkeyed with some relays to keep the fans on or ???

bad coolant temp sensor??