I am dumbfounded. Every time I put the radiator cap on, then it overheats (what appears to be to much pressure). Leave it off then and it is fine. Some coolant gets out of the spout and works fine, but it barley gets above operating temp.. I have replaced the radiator with rebuild 2 years ago. I also have just replaced the water pump and all hoses (top/bottom radiator, new O-ring at pump inlet w/ sm hose from outlet, and heater core hoses). I have a T on the hose to the heater core for purgeing air. I am currently running WITHOUT thermostat. I thought possibly by using a fiber based block seal the I have cause a blockage....but I do get heat from core. Don't know what could be causing the problem. I thought I purged any air through the T. Please advise.

 

Stacy

Since the radiator cap seems to be the variable here, have you tried replacing it? Cheap enough item, so it'd be worth a shot.

 

On a side note, can I have some of your engine temp? I seem to have the only EA82 that overcools! Now that its winter the engine temp gauge barely gets over the lowest tick mark and above the "C." The heat is hardly lukewarm and makes for a chilly drive most mornings. I've tried three different aftermarket parts store thermostats and all three gave me the same temp. Back to an OE Subaru thermostat!

Head gaskets exhibit those symtoms usually. Block sealers rarely work on these engines. Once you overheat them a couple times and they have high mileage already, they will often blow.... I've done a couple where the gasket blew into an adjacent coolant jacket passage, and the leak was small enough that it would use coolant and overheat eventually but otherwise ran fine and tested good on compression.

 

Go to the dealer and get a cap and thermostat and give those a try. Forget about the T - just massage the upper and lower radiator hoses while you are filling the coolant till you get no more air bubbles. Make sure the front of the car is pointing uphill at least a little. These engines are notorious for air bubbles and cheap aftermarket thermostats causing overheating.

 

GD

Since the radiator cap seems to be the variable here, have you tried replacing it? Cheap enough item, so it'd be worth a shot.

 

On a side note, can I have some of your engine temp? I seem to have the only EA82 that overcools! Now that its winter the engine temp gauge barely gets over the lowest tick mark and above the "C." The heat is hardly lukewarm and makes for a chilly drive most mornings. I've tried three different aftermarket parts store thermostats and all three gave me the same temp. Back to an OE Subaru thermostat!

 

Yes, now my motor is overcooling. I have replaced the cap with a Stant 13 psi. Is this the correct pressure rating for the OE cap?

Head gaskets exhibit those symtoms usually. Block sealers rarely work on these engines. Once you overheat them a couple times and they have high mileage already, they will often blow.... I've done a couple where the gasket blew into an adjacent coolant jacket passage, and the leak was small enough that it would use coolant and overheat eventually but otherwise ran fine and tested good on compression.

 

Go to the dealer and get a cap and thermostat and give those a try. Forget about the T - just massage the upper and lower radiator hoses while you are filling the coolant till you get no more air bubbles. Make sure the front of the car is pointing uphill at least a little. These engines are notorious for air bubbles and cheap aftermarket thermostats causing overheating.

 

GD

 

One thing I fail to mention was that that the overflow tank is always empty. Had heads decked and new head gaskets 5 years ago The supect is the radiator cap. The new hose on the heater core blew a hole the same day. The 13 new psi Stant is suspect. Any more ideas?

You have combustion gasses getting into the water jackets. If you are lucky its a HG, if your not it can be a cracked head. How is your oil level?

Pull the plugs and see if they all match, or if one is cleaner then the others (sign of burning water).

 

nipper

You have combustion gasses getting into the water jackets. If you are lucky its a HG, if your not it can be a cracked head.

 

+1.

 

The cap is not the problem. You are getting pressurized exhaust into your coolant and it's causeing the coolant to stop circulating because with the cap in place the gasses have nowhere to go. Air (or exhaust) in the system will cause overheating 100% of the time. With the cap off, the gasses are just escaping out the top. The bubbles are VERY small (small leak = small bubbles), and may look like just so much tiny foam in the coolant as it boils out the top. But if the cap is left in place that little foam will collect into a BIG air bubble.

 

I've never had a problem with new Stant caps - as long as it doesn't release pressure at normal operating temp, I would say it's fine. I have experienced bad behavior from non-OEM thermostats so I usually bite the $13 bullet on those.

 

The fact that you had the HG's done 5 years ago makes them MORE likely as they could have used cheap gaskets. Fel-Pro or OEM are the only two I would consider based on my experience, and feedback from other board members.

 

Overflow is empty cause the engine is burning the coolant.

 

GD

... I seem to have the only EA82 that overcools! ...

 

My EA82 Overcools Too... I Removed the Thermostat Forever!

(Remember: I Live in the Caribbean - No Snow )

Have you Checked the Thermostat?

My EA82 Overcools Too... I Removed the Thermostat Forever!

(Remember: I Live in the Caribbean - No Snow )

Have you Checked the Thermostat?

I too had to run without a thermostat a few years back due to the OEM unit sticking shut (it had ~150K on it at the time, it was due for a replacement). February in northern MN without a thermostat makes for a few days of COLD driving! That's when all this hoo-hah with aftermarket thermostats and overcooling began. Haven't been able to get the car up to temp or the heat to blow as hot as it should ever since. So, it's back to the OE Subie thermost!

 

Back on-topic, G.D. and nipper are spot-on with their statements. The disappearing coolant from the overflow tank has to be going somewhere, and that's into the combustion chamber. Time for a new headgasket(s).

This is my exact problem.

 

Looks like I'll be doing headgaskets in September (or finding a decent EJ22/wiring harness/ecu).

Welcome to EA82 land. I put water in mine every day. Sucks the coolant overflow dry, then fills it up upon boiling. I just pinched the radiator line with a zip tie, keeps it under control

I have the same problem with my ea82.

Uses maybe a quart of water a week driving to work 25 miles a day.

Plenty of cabin heat and engine runs cool as long as everything is topped up.

Funny thing is oil is clean as a pin with not even a hint of coolant.

Coolant also shows no oil contamination.

I figure it's not worth changing head gaskets yet until it gets worse.

Been adding just straight water this summer but will have to start adding anti freeze about mid to late October.

When they overheat, the hottest point is between the cylinders on the head. The notorious leak happens there where the coolant jacket is.