A month ago I really ran my 1988 Subaru hard up the Mount Pilchuck trailhead. Full of pot holes I launched the front end of the car serveral times and got all four tires to spin out on the hairpin turns; I had a lot of fun. The ride was ruff enough to break the PS pump and loosen the ALT mount. Otherwise, the car did great.

However, I noticed with the engine rev'ed up and under heavy loads for the ascent the H2O meter slowly climbed high and stayed there. Not in the red, but a little above the 3/4 mark. On the way down I ran it pretty hard too but I wasn't on the throttle so hard, the temps stayed right at the half way mark. But then on the drive back I noticed it climb back up to the 3/4 mark. Now it just hangs out there. I've checked the obvious stuff. I'm ready to measure the T-stat setpoint on my stove and backflush the coolant system. What do you think is going on here? It's not hot enough to light the fan off and the weather here isn't much warmer then when I stressed the system on Pilchuck. I figure they aren't related, but who knows.....

Maybe you have exhaust getting into the water via bad head gasket?

BTW

The fix was to replace the T-stat. I boiled both in water (new was 193F) (old 190F). At 195 the new one was about 3/4 open the old one was about 1/8 open.

At 210 the new was 100% open and the old was about 1/2 open.

I haven't had an issue since then with H2O temps.

Well I thought I had this licked. This is a riot.

I drove from Seattle to Denver and back for X-mas with the station wagon. I threw my ralley roof rack up top and the wind drag killed me. I averaged over 70mph with gas stops included. Anyhow, whenever I put the fan on med high or high the car would heat up? Also, turning on my fog lights and brights heated up the engine? Anyhow, while in CO I replaced the water pump, I would ahve done the heads but didn't have all the tools.

So on the way back I'm doing fine, but still if I run a lot of electrical loads the car heats up?

A week after I get back I get 1/2 mile down the road and all of a sudden starting from a red light my voltmeter goes to 9V and the radio clicks off. I let off the gas and it goes back up to 12.5V? At the same time the water temp goes very high.

I go back home and try several things. Turns out the ground from the cab to the starter ground was loose and touching the top of the tranny. As I hit the gas it broke contact. Attached the lead and it has run perfect ever since. Love it. Re-did all my ground, now I have perfect charging and rock steady temps, even ralleying around in the snow up high grades in low range.

Well I thought I had this licked. This is a riot.

I drove from Seattle to Denver and back for X-mas with the station wagon. I threw my ralley roof rack up top and the wind drag killed me. I averaged over 70mph with gas stops included. Anyhow, whenever I put the fan on med high or high the car would heat up? Also, turning on my fog lights and brights heated up the engine? Anyhow, while in CO I replaced the water pump, I would ahve done the heads but didn't have all the tools.

So on the way back I'm doing fine, but still if I run a lot of electrical loads the car heats up?

A week after I get back I get 1/2 mile down the road and all of a sudden starting from a red light my voltmeter goes to 9V and the radio clicks off. I let off the gas and it goes back up to 12.5V? At the same time the water temp goes very high.

I go back home and try several things. Turns out the ground from the cab to the starter ground was loose and touching the top of the tranny. As I hit the gas it broke contact. Attached the lead and it has run perfect ever since. Love it. Re-did all my ground, now I have perfect charging and rock steady temps, even ralleying around in the snow up high grades in low range.

I had the same issues with my wagon..Grounds were the key. Do you have a digidash?

No, regular dash. Feel silly it was just a bad ground issue. However, I was glad I replaced the Thermostat since it was sticky.

might have some debris in the rad fins....might want to check that out.