so me and another subie guy went for a mountain ride today. part way through my car overheated. i tried to turn the heater on and i got cool air. so now i'm thinking water pump. we made it off the mountain but it took a while. i topped off the coolant when i got home and left it run for about 10 minutes. i now had heat and the temp was fine. i ran it down the highway and it did fine until i was pulling in the drive way and it heated back up again. i then grabbed my vid camera and took this vid. you can see what it did with the car running and what it did after turning it off. the heater was cooler again. the top rad hose was hot and the coolant is green and not discolored in any way and the oil looks great to. so is it a head gasket or water pump or somthing else??

 

http://s295.photobucket.com/albums/mm132/pamike/subaru/?action=view&current=SANY0088.mp4

Hard to say - when it starts to overheat and the heater core goes cold - is it displacing the coolant into the overflow bottle? If so then either the radiator cap is bad or there is exhaust gasses pressureizing the coolant. That is a typical failure mode for head gaskets. If that's the case you can gain some time by gutting the thermostat but it won't be a permanent repair.

 

Problems of this nature are almost never the water pump. Water pump failure is almost exclusively either leakage out the weep hole or complete sezuire of the pump.

 

GD

the overflow bottle is full when it does this. and when i open the cap their is alot of pressure. it bubbles up in the overflow bottle when i open the cap just enough to release the pressure. also i did notice a slight squeeling a couple of times when i gave it gas but it went away within a few seconds.

how do i know if the pump is seized or not? is their a way to tell without tearing apart? i know it runs off the back side of the belt so i would assume the car would still run with a seized pump

Edited July 31, 201114 yr by pamike

i know it runs off the back side of the belt so i would assume the car would still run with a seized pump

 

not long i don't believe. the belt would die.

 

i would refill and burp. replace the cap. and start saving money.

 

no gunk in the overflow bottle?

 

have you had any recent work done to the car???

nothing in the overflow bottle that i know of. what would that mean? i refilled last night and i ran it around at highway speed and the heater now worked with no overheating for a while but it did heat back up again and pushed the coolant into the overflow.

There are only two possibilities. Either the radiator cap is bad and opening at too low of a pressure, or the head gaskets are bad and allowing exhaust gas to pressurize the coolant to much higher than the rating of the cap.

 

It's almost always the head gaskets. Radiator caps are a pretty rare failure.

 

It is not your water pump. If it were seized it would be makeing aweful noises and smoke from the burning belt. Not to mention it wouldn't last more than a few miles.

 

GD

ok, i just ran it around town for a while and it was fine. when i got back i noticed bubbleing in the overflow tank. so it looks to be head gaskets. so what is happening is it's pressureizing the system, pushing the coolant out and makes it overheat.

what all years of 2.2 engines will swap into my 90? i found one on craigslist that is local to me with like 85,000 miles on it. i'm thinking it might be cheaper/better to just swap in another lower milage engine. my current one is nearing 250,000 miles

90 through 96 will directly bolt-up. 97 and 98 will require changes to the exhaust header as they are single-port heads. Otherwise those will work too. You could also use the 96 to 99 2.5 if you swap out your throttle body and intake manifold wiring harness or use the heads from the 2.2.... frankenmotor style.

 

GD

ok, i just ran it around town for a while and it was fine. when i got back i noticed bubbleing in the overflow tank. so it looks to be head gaskets. so what is happening is it's pressureizing the system, pushing the coolant out and makes it overheat.

 

Yes, a bad H/G will allow exhaust gas to enter the cooling system. That causes a big bubble of hot exhaust gas to form, which interrupts the flow of coolant through the water pump. This further enhances over heating, so coolant and exhaust gas exit out the over flow tank.

90 through 96 will directly bolt-up. 97 and 98 will require changes to the exhaust header as they are single-port heads.

 

i would amend this to read 90 - 95 will fit. every 96 i've seen has a single port exhaust. 96 - 98 will require a different exhaust y-pipe.

 

and the 95 - 96 engines from cars with auto trans will have an EGR on the intake and driver side head. not a big deal, you just do not connect to it since you have no connectors in your car.

ok, if i did this engine swap myself it would be my first time doing this. does anyone have a link to a write-up explaining everything? what is involved in seperating the engine from the auto trans?

I had the same overheating problem on my '90 Legacy wagon. I thought for sure that the heads were leaking. I figured that I had nothing to loose by tearing down the front section of the engine and taking a look at the water pump. Turns out the pump was worn completely out. I replaced the pump, thermostat, timing belts and pulleys. The car runs great now. I certainly can't guarantee that that 's your problem but spending a couple of hours checking the pump sure beats an engine or head change.

Good Luck!

i have a 1990 legacy and it is over heating. when it over heats i can loosen the radiator cap and the gauge goes back 2 normal instantly. the gauge goes to hot after about 2 miles and the cap isent even hot i was told it may be the head gasket any help would be apresheated.