I have a 1997 Legacy L Wagon. With 2.2.  Recently replaced water pump & thermostat. Engine is over-heating and driving me up the wall. I thought I got the air out. I only drive for about 5 minutes before engine overheats and water fills expansion tank. Please Help, I am at my wits end.

Did you remove the heater hoses? And be sure and fill the block via the upper radiator hose and not just the radiator cap.

Replaced both hoses at the pump and yes I did fill the block from upper hose. Could blown head gasket be the issue?

What brand thermostat? Cheapo thermostats don't work well on these.

 

If you start the car from cold and run for about 30 seconds to a minute do you feel pressure in the upper radiator hose?

I will go out and check. Anything else I should check while I'm out there?

Only other thing to check is if it starts pushing bubbles into the overflow container after warming up. Pressure in the system shortly after starting or bubbles in the overflow are signs of bad head gaskets.

Subaru 2.2 motor seldom has head gasket problems, buy yet I had that problem on a 91 Leggie years back. As mentioned, if your replacement thermostat is a "cheapie," that could be your problem. You need to spend around $30 to know that you are buying a good thermostat. Also, did you "burp" the refill on the radiator. It is better to fill the radiator with the car on an incline, as it lets the air out of the radiator easier. Also, loosen the vent plug on the opposite side from the radiator cap. That too, helps to get rid of air in the cooling system.

I was driving my Subaru with the 2.2 today and overheating after some lugging up hills on the hot day; usually the head gasket blow by is manageable, with the bubbles of steam not being out of control.  So I had to pull over, as when I put the heater/defrost on full blast, no heat was coming out.  So when the heater started working again, I was able to drive it at around 65 mph without overheating.  

Once any Subaru overheats, especially repeatedly, the head gaskets are, at the very least, damaged.  Every time it happens, they get worse.  There is no "maybe" about it.  Now, as to what actually caused it, yeah, it could be an air bubble, bad thermostat, failing radiator, coolant leak from hoses, etc, etc, etc.

1.  radiator is clogged

2.  there's a coolant leak and fluid gets low/overheats

3.  headgasket - pushing exhaust gases into the coolant

4.  fans not coming on

Subaru 2.2 motor seldom has head gasket problems, buy yet I had that problem on a 91 Leggie years back. As mentioned, if your replacement thermostat is a "cheapie," that could be your problem. You need to spend around $30 to know that you are buying a good thermostat. Also, did you "burp" the refill on the radiator. It is better to fill the radiator with the car on an incline, as it lets the air out of the radiator easier. Also, loosen the vent plug on the opposite side from the radiator cap. That too, helps to get rid of air in the cooling system.

 

Wow, $30 for a thermostat............  I've never spent more than $20 and the last one I bought from Amazon was around $15 for an OEM Subaru.  

 

That being said, if you search around there are some Stant and another brand that are recommended as well for around $10 to $15.  

 

It's the sub-$10 ones that appear to cause problems (i.e. parts store in house brands, etc...)

I put in a fail-safe thermostat , refilled and bled air from the system. Drove the car about 3 miles when it started overheating. Came right back home and checked. The overflow tank was full. Haynes manual says it could be crank sensor or igniter. Could the timing be off?

Take that crappy fail-safe thermostat out. They are junk! Rock auto has the good stant that is like oem for $10. STANT Part # 48457 

• OKAY. But is it the thermostat causing the issue?

Did it over heat before pump and stat replacement? If not then the stat just may be the problem. It is the cheapest easiest first step to see if it is the problem.

So much drama with this car lately , I honestly don't remember . I think it did overheat but I think that was due to coolant loss via the pump.

96,  2.2, automatic

 

Mine was doing the same thing.   175k miles.  I put new head gasket in.  No more problems

 

The water pushing out into the overflow due to gas bubbles escaping into your coolant via the bad Head Gasket.

 

As fast as yours is doing this.. start the car let it run for 2 min.    Then have someone step on the gas and  look inside your overflow tank..  If you see bubbles ,,,its head gasket.

Edited August 2, 201510 yr by xdeadeye1

Why did you replace the water pump and thermostat to begin with? Was it overheating before you did this work?