thermostat

[happyboy]

I just got a 96 legacy. On the 20 mile drive home, it did not throw off much heat and the temp gage did not move much off of "C". I got a new thermostat and now the heat works ok, but the gage still barely gets over "C". Is something else wrong?

[vrg3]

Maybe you've got air bubbles in the cooling system. Did you thoroughly burp it after changing the thermostat?

[evolutionmovement]

The temp gauge is in a bad place that I think picks up any air bubbles easily, so definitely burp the system. If that doesn't work, then there is air getting into the system somewhere. We'll get to that if it happens.

Steve

[happyboy]

is there some type of standard procedure on how to burp the system? I don't know how to do it.

[happyboy]

Just drove 150 miles. The highest point the gage got to was about 1/3 of the way between C and the middle of the gage. During the drive it would sometimes go below C. Someone suggested the new thermostat I have is set to always run low. Does this make sense?

[petridish38]

Did you get a thermostat along with a new gasket from the dealership?

I had an aftermarket thermostat that would take forever to let the car warm up and would go back to "C" if i revved it over 3,000 RPM.

To burp the system, you need to take the screw out of the passenger side on top of the radiator while filling it.

[Legacy777]

Did you get a thermostat along with a new gasket from the dealership?

I had an aftermarket thermostat that would take forever to let the car warm up and would go back to "C" if i revved it over 3,000 RPM.

To burp the system, you need to take the screw out of the passenger side on top of the radiator while filling it.

Yup.....aftermarket t-stat don't work right in subies.....and ya gotta burp things too....

[petridish38]

OK... Maybe there is more to this problem... I just replaced the thermostat and gasket in my girlfriend's 96 because it was showing signs of a thermostat stuck open (running cold, dropping near C when revved, etc....) Well, after replacing the thermostat and gasket and burping the system, ther problem is still there. I even swapped radiator caps with my car (even though bad rad caps usually cause overheating), and they seem to be working fine.
I dont think the guage is bad because if u rev it while its sitting, the temp will drop, then move back up since there is no air moving over the radiatior. But if you are driving, and downshift, the temp will move toward the C and stay there.
I'm stumped here.....

Andrew

[Legacy777]

just curious.....is the tstat you put in OEM or aftermarket? I'm assuming OEM, but just want to check.

[petridish38]

Old OEM came out, new OEM went in.

Andrew

[Legacy777]

hmmmm, the radiator is the stock, original radiator? What mix of water/antifreeze are you using?

Has the water pump ever been replaced?

[petridish38]

As far as I know, the pump and radiator are stock and original with 72,000 miles on them.

Maybe it is a common thing with 96's or something even though the engines are basically the same (she has the EJ22). I was really expecting to find the thermostat stuck open when I took it out. The car had all the classic signs of a stuck thermostat.

Thanks for the help.

Andrew

[evolutionmovement]

I know my car runs cool (especially with the new engine), but even without a T-stat it did stabilize eventually at a low temp (~1/4 up). Does the heat blow hot?

Steve

[petridish38]

Heat seems to blow adequately warm.

I tried to get the antifreeze mixture as close to 50/50 as possible.

It just worries me every time I see the guage quickly move toward C. I know how aluminum likes to warp.

I don't think I put the thermostat in wrong either.... its not in there backward, and I put it in with the gasket the same way that I put mine in my car. It fit snug.

Andrew

[Legacy777]

Something sounds like it's not working right. The heat in my car will nuke you if you run it full blast for any extended amount of time.

What did the coolant look like when you replaced the t-stat?

[vrg3]

I know you don't think it's the gauge or sender, but maybe you should try using my scantool as a quick sanity check. The ECU uses its own sender.

[professor]

I would test the thermostat, even if it is new. Basically you just dunk it in hot water in the kitchen, and then let the water cool. It should be 100% shut by 160F, as they all open between 175 and 195. Not sure what the exact figure is for Subaru but open at 195 and closed at 160 will work nicely.

Thermostats are cheap, stamped out pieces that probably cost $3 to make, and I have seen bad ones both restricted from fully closing, and stuck closed, on new units.

Here's a link to the procedure

http://www.focushacks.com/index.php?modid=60

The heat should be HOT at full blast, uncomfortable to hold your hand there for long.

[petridish38]

I know you don't think it's the gauge or sender, but maybe you should try using my scantool as a quick sanity check. The ECU uses its own sender.

Well, I actually wanted to do that before I said for sure, but I didn't think the 96 OBDII worked with your scantool. Does it?

Professor, I probably should have tested it first, but I tested the old one right after i took it out and it seems to work good.

Could a partially clogged heater core or heater core line cause enough pressure to push water past the thermostat when its closed or something?

The coolant was nice and clean when it came out since I just replaced it not even 10,000 miles ago when I did the timing belt.

Andrew

[vrg3]

Ohh, right, I forgot you said it was a 96. Maybe you should see if you can borrow a generic OBD-II scan tool or something.

I don't think a clog in the cooling system can create excessive pressure... The water pump doesn't pressurize the coolant, right? It's the heat that does that.