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Overheating on '89 GL


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Right, I've been having a heating problem with my car for about a year. I can compensate by turning my dash heater on all the way, and while that's not a problem during winter (I live in Alaska), it's no fun during the summer. Besides, it's not fixing anything. This is getting to be a problem because sometimes the coolant's getting so hot that it's filling my overflow tank from completely empty to over the "full" line. I had a chat with a mechanic I know from the Subaru shop, and he said I was low on coolant after he had a look. He also said that I probably had a leak. That was six weeks ago, and since, I've probably managed to get a total of another 8oz of fluid into the system (it's full), and I haven't managed to find any leaks at all.

 

I'll go over the bullet points here:

 

-Thermostat is fine

-Radiator fan works

-There's nothing blocking my grill

-There's no indication of any head gasket problems

-No leaks in the line

-The faster I'm going, the more it heats up. Driving on a street at 35MPH doesn't noticeably heat things up, but when I'm cruising down the highway, the temp starts rising.

-The line is circulating (The dash heater wouldn't work otherwise)

 

So, the only thing I can think of is that I've got blockage in my radiator, either from a clog or an air bubble. I'm still open to other possibilities before I try to flush the system and end up throwing away a ton of antifreeze, although I'd like to take care of this before I have to start worrying about the head gaskets.

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The FIRST thing you need to do is a system pressure test. If it can't hold pressure then the system will not transfer heat well, and will eventually run low.

 

Do a pressure check - if you can't see a leak anywhere then it could be an intake manifold gasket (coolant runs through them as well), or the beginning signs of a head gasket although I doubt that. My guess is that you will either find a small leak in one of the little hoses on top of the engine that run to/from the block and manifold or you will determine that the intake gaskets are shot.

 

And don't forget when you are running the pressure test - test the cap too.

 

If it holds 13 psi without any problems - probably time for a new radiator. But unless you have some really nasty, nasty anti-freeze (brown, chunky, etc) then my bet is on a leak.

 

GD

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my younger brother had the exact same problem in his ea81 hatch and after tearing his hair out we discovered his radiator was mostly plugged. there were just two or three tubes passing water so in town it was fine but on the freeway there wasn't enough flow to cool. If you have a no touch thermometer you can see if it's plugged rather easily.

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  • 4 weeks later...

just a couple of thoughts for when you refill the system...

 

1. get the front end up in the air - preferably with the filler neck a little higher than the rest - this will help get the air bubbles up and out of the system. (and they can be a bugger to get ALL air out of!)

 

2. DO NOT use regular tap water in your cooling system!! either buy the premixed 50/50 antifreeze (best choice), or use distilled water to mix. Even city water from the tap will have some minerals in it that are the root of radiator clogs! (well water is even worse!)

 

Good luck! hope your CLR treatment works.

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Didn't work; it's still overheating. I finally said "screw it" and took it back to the shop where me and two mechanic friends were treated to the smell of exhaust rising out of the overflow tank.

 

I've got a cracked head gasket.

 

Time to find a new car.

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