termostat and overheating--'98 forester

[msw]

I have a high milage '98 forester. After a long period w/ very steady low
temperature readings, I was 120 miles into a trip yesterday when it started
to rain. I was driving up a mountain in 5th gear at around 2400 rpms and I
noticed that my gauge was getting hot. It would then cool off when I shifted
to 4th and brought the RPMs up to 3k. This went on for the next 50 miles--
every time the car got below 2800 rpms it would go to about 3/4 the way to
red.

So today I noticed that the coolant was low. I took it to an auto parts
store and a guy who worked there had a Subaru said that it was likely a bad
thermostat. I bought one and changed it. I refilled the radiator and when it
got hot enough for the fan to come on after 15 minutes or so, the temp guage
really spiked. (BTW I could not tell for sure if the old thermostat was bad)

I tried to drive it and had to stop really quickly since it was getting close
to the red--much closer than yesterday.

It didn't exactly seem hot but I am not really sure.

Could this occur if I didn't properly bleed the air out of the system?
Does this sound like the pump may be bad? The guage?
Any advise before I go to a mechanic that I cannot afford?

Thanks, Matt

 

[.._..]

Have you read the dozens (or hundreds) of threads here (use Google Groups)
about gasket problems, coolant refill difficulties, etc etc. yet?

You should. Throwing more money and parts at a car may not discover the
overall issue.

Loss of coolant, overheating and other weirdness can be a hole in the
gasket. (Expensive out of warranty, and a pain in the ass if it is in
warranty.)

For starters, Subarus need special care to get the coolant filled and free
of air pockets, WAY more so than other cars. If your coolant guy didn't
know what to do he's probably NOT helping.

 

[johninKY]

In 45 years of driving I have had exactly one thermostat fail.

Your original problem seems rpm related. Failing water pump, slipping
belt or maybe a clogged radiator comes to mind.

Probably now have a secondary problem with that air pocket you most likely
created by replacing the thermostat. Does the heater blow hot? Got an air
pocket if it blows cold.