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Intermittent Overheating

Posted: Mon Oct 19, 2015 9:25 pm
by valpaval15
Background Info:

So There's a water hose under the intake on the passenger side of the motor that the PO didn't put a clamp on, I guess it built a lot of pressure and a lot of coolant leaked out onto the block. I put a clamp on it and no more leak, I also put some more water into the coolant tank and the overflow bottle. HGs were replaced less than 10k miles ago. Fans work. Water pump also replaced.

Problem:

Literally like 5 minutes after driving it the temp will start to climb (never let it overheat). I would just shut it off while moving and left the power on to let the fans blow. I'd then just roll start (yes it is manual swapped) it after the temp gauge went down. It takes maybe 1 or 2 shutdowns while moving and then I can go on my merry way and it wont heat up at all.

Questions:

Could it just be air in the system?
Did my thermostat happen to go bad at the same time?
What could be wrong?

Re: Intermittent Overheating

Posted: Mon Oct 19, 2015 10:23 pm
by MConte05
So it had a leak, you fixed it, topped it off, now still slightly overheating?

Does sound like the system just needs to be burped, and you have an air pocket stuck if that is the case.

Re: Intermittent Overheating

Posted: Mon Oct 19, 2015 10:45 pm
by mike-tracy
What he said, plus I've had problems with non factory thermostats, and to a lesser degree (no pun intended!) A knock off radiator cap

Re: Intermittent Overheating

Posted: Mon Oct 19, 2015 11:50 pm
by robertpaige
Yeah. Sounds like you got an air bubble in the system.

Re: Intermittent Overheating

Posted: Tue Oct 20, 2015 5:45 pm
by Legacy777
First thing's first, what year and model Legacy is this?

If it's a non-turbo there is a bleeder screw on the passenger side of the radiator that needs to be opened during filling so you get the air out of the system.

If you can provide some more details that will help in troubleshooting your problem.

Thanks

Re: Intermittent Overheating

Posted: Tue Oct 20, 2015 6:26 pm
by valpaval15
Oh well that's embarrassing, I thought I wrote down what car I had. It's a 1993 Legacy TW. What's weird is I did burp the system, maybe not well enough from the looks of it.

Re: Intermittent Overheating

Posted: Wed Oct 21, 2015 6:22 pm
by Legacy777
If you're running a stock radiator and cooling system the turbo radiator has a line that vents the radiator to relieve trapped air. These still can be a little challenging to burp, so you could try putting the car on an incline with the nose up.


Also, what brand thermostat are you using? If it's anything but a Subaru tstat that could cause you problems.

Re: Intermittent Overheating

Posted: Wed Oct 21, 2015 8:57 pm
by valpaval15
I don't actually know because I haven't changed the thermostat, but good news. I brought it home while it was starting to heat up and i just opened the radiator cap enough for steam to come out, as soon as water started to come out I just closed the cap really quick.

Now it works beautifully again! Thanks guys for all the help. And what line were you referring to? I have the stock radiator but I never noticed any lines other than the upper and lower radiator hose as well as the hoses that go to the coolant tank (not the overflow tank).

Re: Intermittent Overheating

Posted: Fri Oct 23, 2015 5:37 pm
by Legacy777
The turbo radiator has a small coolant line just above the upper radiator hose that connects to the coolant expansion tank. Does yours have this?

And this is why I asked what model you have. The cooling system is different between the turbo and non-turbo engines. I am making an assuming that you have the stock radiator setup on the touring wagon, which was turbo.

In reading your last post, you mentioned you opened the radiator cap, was this opening the cap on the radiator or the coolant expansion tank?

Re: Intermittent Overheating

Posted: Sun Oct 25, 2015 10:03 am
by valpaval15
The expansion tank cap, and it does have that line I just didn't know it was for that purpose. And yes it is the stock rad in my turbo wagon.

Re: Intermittent Overheating

Posted: Sun Oct 25, 2015 11:42 pm
by Legacy777
Ok, well hopefully it was just trapped air and you got it sorted out.