G'day & Welcome aboard @FozzyXT2012

Assuming the thermostat was working OK before the radiator change would suggest there is an air lock. There's nothing frozen is there as that will give a similar issue.

 

Thank you!

Nothings frozen, if you mean frozen from the weather, then definitely not. It’s been in the 50’s ferinhieght all week. I had it on ramps trying to bleed the system, even parking it up hill, since my driveway has a decent incline. And no luck.

 

Did you use a coolant funnel? Are the fans working? Did you let the fans cycle on 3 times? If the thermostat was working before the rad replacement, I doubt that is the problem. Was the new radiator OEM?

 

No funnel, I made a huge mess :/ Fans are working. The new radiator is a Denso I ordered from RockAuto.com I read on another forum, that a closed thermostat could split the radiator, the plastic tank from the aluminum core. Thats how my radiator broke. I'm really hoping its just air locked, I don't want to have to waste all the new coolant changing the thermostat. That stuff was EXPENSIVE! And it was pre-mixed, and got 2 gallons. So I paid 28 dollars for one gallon of water! That crap is a scam. when I worked at a parts store years ago, I always had people buy the straight coolant, not the pre-mixed one. Why pay for something that has half water in it, when you can buy a gallon of straight coolant, and you can make 2 gallons of pre-mixed coolant from it!

 

Assuming the coolant is good, you could drain it and reuse it.

 

Yeah I’m gonna try that.

 

Subaru engine coolant system bleeding process - hints & tips | Strong for Subaru

Finding it tricky to bleed air from the cooling system when youre fitting a replacement Subaru engine or radiator? Heres how you do it

strongforsubaru.com

Go with this and everything will be fine.

Sent from my SM-A705FN using Tapatalk

 

If you re use the coolant, make sure it’s free of any particles. You can even filter it. I agree, too expensive.

The Subaru super coolant used to be sold as a concentrate that water could be added to, in different ratios.
See: YT video by Mr Subaru on coolant replacement. Letting the car sit overnight? Not necessary.

 

Update: Replaced the thermostat with a Subaru OEM one, and all is right with world!!! Should have not been lazy, and replaced the thermostat when I replaced the radiator.

I guess that’s what caused the old radiator to blow. Huh.

 

Good news! I'll add "solved" to the title

 

Awesome!

 

For what it's worth, your post has convinced me to change the thermostat when changing my radiator.
At least we get to learn from each other's experiences!

 

Definitely! And it’s easy as heck to change!

 

Quick question Fozzy XT. When you replaced the thermostat did you get a significant amount of extra coolant to come out of the engine block? I want to change as much as I can. The service manual shows nothing about an engine coolant drain plug. Just says to drain from the rad but that I suspect only lets about 4 Litres out. Does nobody use a coolant flush, or even just repeated drains and fill with just distilled water, and then calculate the amount of concentrate to use? It seems strange to me there is nothing about this in the service manual. Also assuming I have the front end of the vehicle raised when removing the thermostat, should I lower it back to level to get more coolant out, and then afterward jack up the front end to fill and bleed the air?

And FYI for anyone, Prestone now sells premix blue coolant for Acura, Honda, Nissan, Infiniti and Subaru, and it is on sale presently at Wal-Mart for 1/2 price or $14.47 Cdn a jug. I can also buy a similar private OEM label coolant in either concentrate or pre-mix at Canadian Tire. I have no concerns about using either

 

When I popped off the thermostat, I’d say about a gallon of coolant came out. I had my Forester on ramps when I did it. After everything was buttoned up I poured maybe a gallon and a half back into the system. Checked the level the next day before driving it, and didn’t have to add anymore.
Bleeding it was quick this time! I still had it on the ramps when I did the bleeding, and it took no time for it to get sorted out. Pretty much filled it, let it get to temp, and filled till I couldn’t fill no more. Drove it right after, no problems.

 

Thanks for the answer, So basically just to be clear-- extra coolant came out in addition to what came out when you drained the rad?

 

Yes.

 

Well, I bought the thermostat from the dealer so hopefully, the weather is good enough tomorrow to do the job. Was thinking of being cheap and not replacing the existing one which is working fine, but I may as well do a good job.
Part number 21210AA181 includes the gasket-- 45.97 Cdn and I note its made in Japan.

 

Awesome! I hope everything goes smoothly for you.

 

Well I haven't changed the rad yet as it has somehow stopped leaking and I am not losing any coolant. The weather is still too cool for me to want to leap at the job.
When I was looking under the car today, I took a look at the thermostat location and it has me wondering --do I need to undo the exhaust manifold and drop the exhaust to remove it? Or is there enough room to get at it and change it without doing so? I have a 2011 with the FB25 engine.

 

Nope. Don’t have to mess with the exhaust at all.

 

Thanks for the answer. I will see if I can get a socket in there and access both bolts. Space is really tight. I may take a picture to share tomorrow.

 

Do you have the factory plastic “skid” plate? Take that off and it opens up the area nicely. You’ll be able to almost stick your head in between the radiator and engine lol.

 

FYI I have been looking at the service manual for my model with the FB25 engine and you do need to drop the front exhaust-- argh... For fun, I also looked for the XT and you don't need to with yours. Sadly one of the bolts on mine is simply not accessible, and even if it were I don't think there is room to remove the thermostat cover to swap out the thermostat. Why did they have to make such a simple part so inaccessible?

 

Aww man. That sucks! Time to sell it, and get an XT!! Lol just kidding. Looks like you have a bigger project than expected, hope it goes as smoothly as possible when you decide to go at it!

 

Just means I will live with the one in place until the sad day comes when I need to have the engine pulled to reseal it. Not sure when that might be, but it is weeping a bit of oil on the driver's side, and possibly the timing chain cover. Not really losing much coolant despite the telltale blue staining on top of the rad where the plastic meets the aluminum. However, that is dry. Still, the plan is to replace the rad next week and to change the coolant and transmission fluid.