5 replies to this topic

[dmt]

Hey guys, quick question. I've noticed a leak where the thermostat housing joins the engine block, subaru have advised me that there is only the rubber gasket inside securing the thermostat and no paper gasket. Can anyone confirm this? Seems to me like there should be a paper gasket, and if there is does anyone have the part no? Thanks David

[XXB4XX]

Hey guys, quick question.

I've noticed a leak where the thermostat housing joins the engine block, subaru have advised me that there is only the rubber gasket inside securing the thermostat and no paper gasket. Can anyone confirm this?

Seems to me like there should be a paper gasket, and if there is does anyone have the part no?

Thanks
David

Hey dude, best getting the VIN number and getting the gasket from Subaru.. mine on the B4 had a rubber / grommet type gasket as well.. what model is your car?

If like the GenIII and most others I gather, your thermostat is a part of the waterpump assembly and is a pain to get to.. good luck!

[RX25SE]

Rubber only.
Sits around the thermostat and seals to housing and engine.

If you're replacing it, replacing it do the thermostat also and flush out the system. Maybe even replace the radiator cap.
Might as well as you will need to drain the system.

Make sure you bleed out all the air.

These parts are available aftermarket if Subaru charges are excessive.

[dmt]

Its a GEN3 GX, luckily its not part of the waterpump assembly, simply bolted onto the bottom of the block. Yeah i was thinking of replacing the thermostat while im at it, do you know roughly how much do aftermarket ones cost? Correct me if I'm wrong but process for bleeding the system: park on incline with front end higher, fill radiator, run car for a couple of minutes to let it warm up, fill up again and jiggle top header tube to get rid of air bubbles? Do i also need to run it without the radiator cap on for a while? Thanks David

[Scuba-Roo]

Rubber gasket only, I put some gasket goo around the housing bit once. On gen1s theirs a little plastic bolt on the opposite side to the filler cap, that's how I've bled the system. Thermostat from Subaru should be ~$30 then the rubber was $3-$4

[RX25SE]

For 30 bucks, go to Subaru.

Make sure you flush the system out with fresh water, leave thermostat housing off and remove one heater hose and flush in both directions. ie. into the heater and into the motor. Then flush radiator from the bottom and again from heater. Do this until all traces of old coolant has gone.
Mixing different types/brands of coolant can sometimes cause a reaction that makes a crusty residue which blocks the system.

Refit thermostat and housing, leave heater hose disconnected and fill the system slowly. Set hose on a dribble, and allow to fill (grab beer while waiting), when water starts to appear at disconnected heater, reconnect hose and remove bleed nipple from RH top of radiator. Add new coolant slowly.

Continue to fill at a dribble (drink said beer while waiting) until water/coolant appears at bleeder. Car nose up on hill works better.
Fit bleeder and start engine with heater on full and fan on 1 and allow to warm up. Keep an eye on water level and temp gauge (while continuing to drink beer) and make sure heater gets hot.
Open bleeder a couple of times to check for air.
Make sure overflow bottle is up to top mark.

Once cooling fans have cycled, fit radiator cap and shut off engine.
Allow too cool. (More beer while waiting)

Check water level in radiator and overflow.

Run engine again with system sealed and as engine warms up loosen (don't remove as hot coolant may gush out) bleeder to let out any air.
You may need to do this more than once.

Allow to cool, recheck levels.

Do NOT road test as you have been drinking!

Actually forget the beer bit. This can be quite dangerous if you're not careful.
WARNING:
A HOT COOLING SYSTEM UNDER PRESSURE MAY INSTANTLY BOIL WITHOUT NOTICE.
THIS HAS THE POTENTIAL TO CAUSE SEVERE BURNS.