legacycentral bbs

i started overheating on the interstate (when i turned heat from high to off position), pulled over, let things cool down, added some more fluid and continued home w/o any issues for another 50 miles at normal temp.

The next time i drove it it was fine for about 40 minutes, then when i adjusted the climate control (from high heat to off position) it immediately started over heating again. figured it had to be thermostat related, so i replaced the thermostat.

First time driving it again and it seemed fine for about 15 minutes until i touched the climate controls (went from off position to high heat on) and bam, temp starts shooting up. Any ideas what could be going on? I did my headgaskets and water pump about 500 miles ago

97 legacy 2.5 GT

It sounds like your radiator is not doing it's job. This could be from blockage, faulty thermostat, collapsed hose, etc. anything that would not let water flow through the radiator.

Your heater is the substitute when your using it. When your not using the heater there is no release for the coolant and temps go up.

Since the last time your car overheated when you turned the heat on, I would say there is something else going on. I believe coolant flows through the heater core at all times and when you turn the heat on you are only opening a flapper to allow heat into the car. It is a good idea to turn the heat on and the blower to high if your car is overheating as this is just another way of dissipating the heat.

I am thinking that you have an electrical issue or maybe a cable rubbing on an electrical wire. You really need to find out if your car is actually overheating or the gauge is just reading that it is.

Jeff

i saw how hot it was one of the times before changing the tstat. coolant was pissing out the vent valve in the overflow rezy.

i will try to get all that air out

FWIW>
I went through a similar ordeal with my '90. Replaced: the t'stat, water pump, all hoses, radiator, even the engine at one point. Turns out that my heater core had a pin hole, or some issue anyhow, with it and was causing over heating intermittently. However for the life of me, I can not figure out why it would cause a problem when changing the heater controls from hot to a cooler setting, then be fine after cooling down and topping off the radiator, but it did and has not caused me any problem since I took countermeasures.

The first obvious thing that I had a core issue was excessive fogging of the windshield, and all windows for that matter. On that day I bypassed the heater core under the hood, it was only about 25 to 30 degrees that day so it wasn't that bad. LOL. Had to leave it bypassed for the rest of that week, then, on the weekend I reconnected the core, pulled the t'stat and tested it and it was fine. I left it out as to not put pressure on the core and use a radiator sealer, from Autozone. I know that this is only temporary and I will be properly addressing the issue this summer, but it has so far gotten me though the harshest part of the winter without loss of heat to me or excessive heat to the cars engine.

Oh, I blocked the front of the radiator with a large piece of cardboard after nearly freezing to death on the freeway. LOL. It has been running right at the halfway point on the temp gauge since. Takes a little longer to warm up too.

Yeah do try to bleed any air out of the system. I'm not sure on the 2.5 of that year whether the radiator had a bleeder screw on the passenger side of the radiator or not. If it does, make sure to remove it when bleeding.

Also, is your thermostat a Subaru thermostat? If not, get a Subaru one.

Like Ryan mentioned, to test whether the heater core is ok, you can bypass it and see if your problem is still there or not.

Actually, ryan mentioned something about keeping an open mind and not making fun of those who do.

That quote on my sig is confusing I'll see if I can clean it up.

That's better

But for sure you can bypass the core for testing purposes. You possibly will want to choose a time of year that is warmer, or, as in my case, it was necessary to just do it in the dead of winter. If that's how it has to be, then bundle up!