Strange coolant problem with 2003 ez30d

[laegion]

So. I bought a 2003 Outback LL Bean with 196k. The car is in reasonable shape and runs pretty well except a slight hesitation and sometimes it idles a little rough/vibrates at idle.

The main issue I'm having is that it likes to kick out about 1-2 cups of coolant every time I top off the radiator, it doesn't seem to keep pushing out coolant after that but it will have a very slow bubbling from the overflow hose into the tank at idle.

I tested with a combustion gas test kit and after 2-3 min of testing the fluid hadn't changed color in any noticeable way.

I do not see any active coolant leaks, maybe there is some seeping slowly but not that I can find. The only time I see coolant actually leaking from the car is if I keep topping off the radiator without removing some from the overflow. Also no strange smoke on cold starts, no contamination in the oil or transmission fluid.

Currently I can just top off the radiator every morning and drive it all day (about 100 miles a day of stop and go traffic) and it never overheats; although the primary radiator fan does run a bit more than I'm used to with my other car (95 ej22) but that's it.

I have replaced the radiator cap with a "safety" style and an OEM cap is on order; but I haven't changed anything else.

I'm thinking a coolant flush, new OEM radiator cap and thermostat would be a good start but I'm not sure if any of those (besides the cap) could cause this issue and I'm wondering if I'm seeing the start of a head gasket failure but not enough at idle to show up on a test? Maybe a partially clogged radiator?

Any ideas or advice are welcome; especially if you have experience with similar issues with an ez30d. (aside from things like telling my my engine sucks or I should buy another car...lol)

[idosubaru]

That’s too bad. unfortunately used H6s are prime candidates for dumping for sale due to the way they easily sneak through with mild and “unconventional” symptoms

Burp it. New coolant and burped will take care of that.  But it’s the headgaskets.

Before filling radiator run a garden hose through it and make sure it can pass the water (not clogged).  Sometimes that’s nicer to do off the vehicle if you don’t mind pulling the radiator. Or get a new radiator. 

New cap and tstat can be tried now and transferred to new engine.

Exhaust gas analyzer will give you a positive result when the combustion test kit doesn’t.

[GeneralDisorder]

Yep. Head gasket failure. Replace the engine with a JDM if you want to keep it. Otherwise it's scrap. 

GD

[laegion]

Well then, anyone know a reliable importer? I'm in the PNW if that makes any difference. It seems shipping to the lower 48 is usually pretty universal.

 

[GeneralDisorder]

Foreign Engines Inc. in Lynwood, WA

GD

[ThosL]

I've run Subarus with head gasket issues for a while after the problem gets noticed.  Is it overheating? The Subaru approved treatment may help a little.  Other fixes in a bottle usually do little. You could pull out the thermostat or run with less pressure.  

The experts can of course correct me if I'm wrong.

Edited September 26, 2021 by ThosL

[laegion]

2 hours ago, ThosL said:

I've run Subarus with head gasket issues for a while after the problem gets noticed.  Is it overheating? The Subaru approved treatment may help a little.  Other fixes in a bottle usually do little. You could pull out the thermostat or run with less pressure.  

The experts can of course correct me if I'm wrong.

It's not overheating, it does get a bit warm if it idles for too long, if I haven't topped off the radiator recent enough. If I didn't drive for work it would barely be an issue.

[laegion]

4 hours ago, GeneralDisorder said:

Foreign Engines Inc. in Lynwood, WA

GD

Thank you. I'll check them out.