Non-turbo 90 Legacy wagon overheating

[912126]

(Earlier years - Replaced radiator, water pump, timing belt..)

Pre-19th - Noticed coolant was disappearing. Added coolant to both radiator & OF tank. Started carrying extra coolant in car.

August 19 - After several hours of driving and cooling down, on the way home car over-heated, emptied out the overflow tank, and died. Allowing it to cool enough to add coolant did not fix the problem. Towed to the end of the (I-95) bridge and parked.

August 20 - Filled the radiator and OF tank. Installed new radiator cap. Drove about 4 miles and had to pull over due to overheating. Cooling down enough to add water didn't help. Crept home.

August 22 - Replaced the thermostat.

August 23 - Drove 2 miles, stopped 10 minutes, drove 2 miles home. No problems.

August 24 - Drove 2 miles. Stopped for 5 minutes, started and drove around the block, overheated. Cooled and crept home.

August 25 - Removed timing belt. Some engine oil in TB compartment. De-greased belt, pulleys,

Re-assembled. Removed, compressed and re-installed tensioner all the way left and up.

Filled radiator and OF tank with coolant. Ran for 5 minutes. Moved car to incline. Cooled down. Added another 1.5 liters coolant to radiator.

August 29 - Drove 2 miles, stopped, and drove home. No problems. Several hours later attempted to check coolant level. Opened cap, coolant poured out.

Drove car 15 miles stop and go. No problem.

August 30 - Coolant low in radiator and OF tank. Added 2 liters to radiator and 0.5 liter to OF tank. Drove 2 miles, stopped for 5 minutes. Started car, temp gauge swung to red zone.

Crept home. Near home, OF tank overflowed. Cooled, added 2 liters coolant. (Total engine coolant is 6 liters.)

August 31 - Removed thermostat. Removed AC condenser coil. Drove 1 mile out, 1 mile back. No problem.

September 05 - Drove car all over. No problems.

September 11 - Added 210 mL water to fill radiator. Drove car 2 miles out, 2 miles back. No problems. Cooled down. Checked coolant. Radiator full, OF tank above Full.

(No bubbles in OF tank ever, except just after engine is shut off.)

What with the explosive expulsion of coolant through the overflow tank, I found it difficult to determine if coolant was leaking out. Now that we can drive without an incident, it seems clear coolant is disappearing. There is no apparent leaking of fluid. So, I'm thinking it is spraying an invisible mist during driving. (tiny hole) But I understand it can also leak into the combustion chambers. Any ideas on how to determine which it is?

All comments appreciated.

[Legacy777]

Did you use a Subaru thermostat? If not, you need to.

Additionally, there is a bleeder screw on the opposite side of the radiator fill cap that needs to be removed so you can properly bleed the air out of the system.

If you did both of those things and still have issues, I would suspect you may have a head gasket issue.

[912126]

Thanks for the help Josh.

The thermostat is a Stant #48457. As mentioned, currently have no thermostat installed.

Have used the bleeder screw.

Yesterday, after a 25-mile, 1-hour trip I added 300 mL of coolant to fill radiator.
As traffic changed, the temperature gauge ran up and down, but never came above horizontal (3:00) position.

Thanks again

Dale

[Legacy777]

That stant supposedly has the same characteristics of the Subaru t-stat. I've never used it.

Again....the symptoms are pointing towards a head gasket.

[912126]

I agree.

I'm thinking about using a can of sealant. Any experiences? (Good or Bad)
I'd like to eliminate a radiator leak as a possibility. But if it fails a pressure test, couldn't it just be because there is a leak in the head gasket? ( as opposed to a leak in the radiator, pump, hoses, etc.?)

Would it be better to just check the compression in each cylinder? But differences in pressure could also be caused by something else, right?

I add a few ounces of water after each trip. Have had no incidents. But I will need to resolve this before weather turns too cold.

Thanks for the help.

Dale

[rallyak]

If your talking about that block seal stuff that's suppose to fix head gaskets, don't waste your money.

[Legacy777]

Yeah....don't put that sealant stuff in, it will clog up your radiator and heater core and pretty much make a nasty mess in the cooling system.