Low coolant?

[no1withthisid]

I'm having some troubles with my wrx.

During idle my heater doesn't blow hot air, and my car starts to slowly overheat (114C) if i rev the car to 2.5k rpm the temp drops back down to the normal 1/3 mark. the heat works perfect when driving and the car never overheats (86C)
I checked my coolant and it seems low? The plastic overflow tank is almost empty and the filler tank next to the turbo seems a bit low.

Both of the fans do turn on at idle.

How much coolant should be in tank next to the turbo?


Could this be cause of the heater problem?

[SD_GR]

If you have not done any recent work on the car requiring you to open the cooling system, pressure test the cooling system and/or look for a leak.

If you have done recent work on the car requiring you to open the cooling system, burp the cooling system.

[no1withthisid]

I will burp the system and change the thermostat. I'm just wondering what should the coolant level be in the tank next to the turbo? Should it be completely full?

[SD_GR]

The level will vary between the two lines.

[SD_GR]

If you think it is the thermostat, buy an authentic Subaru replacement, use an authentic gasket, and use Subaru coolant (the new blue coolant is fine and premixed). Make sure first though.

[no1withthisid]

I'm not seeing any lines in the metal filler tank next to the turbo, my plastic overflow tank also has no lines as it is not oem due to my fmic.

The coolant level is just slightly about the bottom of tank next to the turbo while the plastic overflow tank is basically empty.

[SD_GR]

Turbo reservoir should be full, other reservoir midway but variable. Have you pressure tested the system? Have you opened the system for any reason? When and why?

[no1withthisid]

No pressure testing and and I have not opened it. Should I add coolant directly to the turbo reservoir?

[SD_GR]

Add coolant to the reservoir, top off the overflow container, and burp the system.

All this is a bit of a waste though if you cannot confirm there is no leak. Pressure test the system.