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Continuing my fight with my 91 Legacy, I went out today, removed the air blled plug and addied coolant to the radiator. Resivour is at full. Fired up the motor and let it idle. During the time it took to warm up, I added a bit of coolant from time to time, but not much. Once it was up to temp, the heat was blowing cold. Also, the upper radfiator hose was cool and soft. Although it is very difficult to see into the radiator, there was no apparant "flow". Neither did the cap opening "steam" as I might have expected, its only 3 degrees F out. It sat at warm idle for perhaps 10 minutes. Put the car in gear and drove, literally, 100 feet MAX and the guage took off right to hot. Shut it down and popped the hood, the upper hose was warmer than it had been at idle.

Also, while at idle, the fans both came on properly.

Am I correct in asuming that the thermostat is working properly because the temp held steady at idle? I have the sinking feeling that this is going to be a head gasket, but I'm sure hoping that perhaps the radiator is largely clogged? It was replaced by the previous owner at some point and was a used one that was installed. There is no white smoke in the exhaust, not coolant in the oil.

I'm bumming over this, it's my only transportation, other than the "Shoeleather Express"!

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Recently, someone posted a link on how to trouble shoot cooling system problems. I remember that a sure sign of a clogged rad is if it's cold at the bottom and hot at the top or hot at the bottom and cold at the top. You check this when the engine is at operating temp or when overheating.

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The hot top, cold bottom hose is a sign of bad circulation. This can be caused by blockages, worn/loose water pump impeller, or "vapour-lock" in the water pump.

 

Vapour-lock can be caused by compression and exhaust gases leaking into the coolant, across a tiny leak in the head gasket. The pressure drop across the pump has a tendency to expand the bubbles and when enought of them collect in the pump, there is no circulation.

 

Not what you wanna hear is it?

 

By all means, flush your radiator, but start thinking about replacing head gaskets. You might be able to bide your time by fitting a higher pressure radiator cap. I believe your model is 0.9 Bar. Newer models are 1.1 Bar. Might be worth getting a brand new 1.1 from a dealer to see if you can control the overheating until money drops from the sky and you can afford the HG work.

 

Dang it! Why must head gaskets fail???

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Many others here are much more experienced and knowledgeable than I am, but I had something similar happening with my 95 2.2 a couple months ago. I had done absolutely nothing to the cooling system since I started driving the car, and it had always operated fine. Then, one night my heater went cool and the temp was higher than usual, but not at the danger zone. No previous Sube experience, but I figured it was the thermostat, so I bought a new one and swapped them. That was a major pain because the replacemen thermostat's o-ring rubber gasket didn't seal 100% and I kept getting a leak until I figured I needed to just use the old gasket on the new thermostat. That aside, it wasn't that big a hassle of a job.

 

 

Anyway, after a few days of driving I started overheating big time one afternoon. At first I thought maybe it was a bad water pump, but that didn't seem to be the case. I didn't know what to do after i checked fluid level, etc. The coolant looked almost completely full, but I decided to add a little with the engine running. I touched the upper radiator hose to feel for flow--didn't feel any, and then I squeezed it tight. When I let go, the radiator gurggled and the fluid level dropped. I "milked" the hose like this a few more times by squeezing it. Then I added the coolant slowly, doing the squeeze and gurgle periodically during the process. Not had a degree over that middle normal operating temp range since.

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1. Get rid of any air in the system.

Jack up the side of the car that the bleed screw is on. Use your MityVac adapted to the bleed hole and suck out air. Reducing pressure will expand and burp out more trapped air than you will normaly get by other methods.

 

There may be air in the heater core too which would help explain no heat or it could be no circulation.

 

2. Check circulatiion.

At these cold temps, I wouldn't expect to see continous circulation, but you need to determine if the pump is bad or if the thermostat is not opening.

If you don't see circulation, take out the t'stat and check circulation again. REPLACE with a new Subaru part. Burp like above or some other proven way.

Replace pump if no circulation.

 

3. Check for leaks

Find the leak you mentioned and fix it. Replace hoses or radiator until it's leak free. A leak will not allow coolant in the resivoir to be drawn back into a cooling engine. You'll never get rid or trapped air.

 

4. Head gasket

With no oil or crap in the overflow tank you may be OK. There are test kits to try before you take the engine apart. 2.2's are not known for gasket issues, but if you over heated the engine, you may be in trouble.

 

Keep it running as long as you can.

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It appears the crux of the problem was that the fadiator "slush-froze" in the extreme cold we had been having. With nowhere to bring it inside, the slush was going nowhere, so circulation was, if not nil, close to it. Very hard to get heat to the radiator from an external source, not much grill area and theres a pan under the radiator that pretty much prevented heat from rising to it. But, the weather moderated a bit, I put it out where the sun could help a little, shrouded the engine compartment with an old blanket and placed one of those little ceramic heaters under the front a little ways. Let that run for 5-6 hours anyway. Mixed up a batch of 2/3-1/3 anti freeze proper like and kept introducing it to the radiator a little at a time. I'm not convinced I've all the air out yet,, but the sealant has apparantly plugged the leak in the radiator and I've ran it on a couple-three 5 mile or so jaunts with no problem, needle is staying right where it should be. That was just yesterday. I still plan to replace the radiator, should pick the new one up tuesday or wednesday. Then I get to change the ball joint, oil change, and hopefully I'll be good to go. Literaly "to go", I'm planning on moving to NC as soon as the car is up to snuff. Bought it right, and I'll have replaced the windshield, radiator, and ball joint in the bargain. looking foward to many miles more from it.

SS, I notice your signature sez 91 Legacy AWD, while mine car sez 4WD.

??????

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1. Get rid of any air in the system.

Jack up the side of the car that the bleed screw is on. Use your MityVac adapted to the bleed hole and suck out air. Reducing pressure will expand and burp out more trapped air than you will normaly get by other methods.

 

There may be air in the heater core too which would help explain no heat or it could be no circulation.

Hi, I have a similar issue in my Legacy, the temp rises once in a while in the wake of a thermostat replacement. Which of the MityVac products is the right one to use for this, and does it come with an appropriate adapter? Thanks!
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I just have a little, basic hand pump. I connect some hose and wrap one of the adapters with enough masking tape to make it seal into the radiator. It would help to have a litle reservoir in line so you don't pump the fluid into the pump. I think the new ones come with one.

Hope this helps.

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