Bubbling in overflow, many repairs to fix it

[novakdesolation]

Another update, I can't even get a mile down the road without it hitting 240 so I've pulled over so I can wait for it to cool. I have the key on on, with the engine off, and can hear the rad fans. And while typing this I had the engine open and when the rad fans turned off it sucked out almost all the coolant from the overflow. Does that sound like a head gasket or something else?

[1 Lucky Texan]

well, there is a chemical test for combustion gasses in the coolant. But generally, bubbles means bad HGs.

the chemical is a liquid and the engine must be generating the bubbles to go up thru the liquid. It turns from blue to blue-green. You can find youtube videos for it.

the only other crazy idea I can think of is bad waterpump/slipping TB on water pump.

[novakdesolation]

It is especially weird because after waiting about 7 mins the temp was normal. Got back on the road to test and it spiked to 201 but went down to 194 and stayed there, I have been idling in my driveway for about 5 mins and it won't go above 201, the rad fans kick and bring it down to 186. Also if it seems weird that I have exact temps, I have a Bluetooth obd2 scanner that hooks up to my phone, so the temps are coming straight from the ecu

[signage]

It could be a bad Thermostat. But if it is happening consistently while driving on the highway, I would say that points more toward a HG, as when the engine is running at constant higher RPM it is acting like a compressor to the cooling system. Which is causing higher pressure in the system causing the cap to open and allow coolant to the overflow bottle. Then after this high pressure is bleed off after stopping, the temperature raises and the thermostat operates and the coolant is drawn back in.

[novakdesolation]

The thermostat makes sense, it was only half of the trip, after the few mins with the engine off, it worked fine. Also I let it idle in my driveway for a bit to see, and although it didn't overheat, there was steam being kicked out from under the radiator. Not sure if that helps but I just wanted to put all the symptoms as they come

[signage]

Cheapest and easist would be to get a Subaru Thermostat and Radiator cap from you local dealer! Replace them and hope it fixes it.

[1 Lucky Texan]

oh yeah, 'standard' t'stats are known problems. figured at this point in the conversation that would have been covered.

OEM, stant Xacstat, maybe others, are mandatory for soobs. larger wax capsule and 170 deg temps.

[novakdesolation]

I called one shop that the last owner went to that replaced the radiator and thermostat, and they said they only used OEM parts, except the radiator, they went with an aftermarket part for that. so next stop is the other shop to see the type of head gasket used. Other than that would a cracked block/head lead to this kind of intermittent problem? I feel as though it would be a constant problem at that point, correct me if I'm wrong though lol

[novakdesolation]

OK and the second shop stated they used Subaru head gasket parts on the replacement. I'm going to call back the first place and see if they used what you recommended 1 lucky texan

[1 Lucky Texan]

from what I've read, many people have the same type symptoms as you from HGs and just as weird symptoms from bad t'stats. Something abot the t'stats, they seem to get too cool when the car is moving and close when a 170deg OEM with the large wax capsule stays open.

I think I'm just hoping you have a bad t'stat or waterpump but, if the car has bubbles and coolant is flowing, those bubbles are quite likely combustion gasses. Quite typical to only leak one way and not usually have coolant in the exhaust. I think some shops can also use a tailpipe 'sniffer' to confirm the bubbles are combustion gasses.