This comes up a lot it seems, we are often directed to a forum link or told that a Subaru dealer is stating something different than what is in the owner’s manual.
What I can tell you is that just like a software update after the software is produced as a result of something learned about behavior in the field Subaru will address things that come up that can negatively affect the ownership experience. This is especially true when Subaru changed the oil change requirements to maintain warranty coverage on all Turbo models to 3750 miles instead of the Fantasy that is 7k interval oil changes that was printed in the owner’s manual. Some Subaru Dealers are in fact suggesting cooling system services that differ from what Subaru printed in the manual I think they are correct in doing so.
I will do my best to try and explain which coolant is right for your Subaru at this time.
If you own a 1990 to 2002 2.2l or a 1995 to 1999 DOHC 2.5l you can use just about any type of regular Green Antifreeze/coolant. You do not need to add any type of stop leak, I mean coolant conditioner, the service interval is every 30,000 or about every 2 years on average. This will hold true in most all Subaru Outbacks, Impreza, Forester, Legacy and WRX models.
If you own a 1999 to 2008 SOHC 2.5l you should use the O.E. Subaru Long Life Coolant that is green in color pictured below. If you have not had the Head Gaskets replaced or they were done at the Dealer you should also use the Cooling system conditioner as well. If you have had the Head gaskets replaced and the shop that made the repairs used the Six Star gaskets you can use normal green coolant and DO NOT need to put any stop leak I mean conditioner in the cooling system.
Starting in 2008 Subaru went to a new Super long life coolant, it was only supposed to be in the STI in 2008 and all other models by 2009 but we have observed plenty of 2008 Subaru Outback’s that came from the factory with Blue Super long life coolant rather than the green long life. If what is in your car is green it needs to be changed every 30k, and if blue every 60k, if you want to try and go 100k you do so at the real risk of repairs down the road.
We have heard reports that some Dealers have stopped carrying the Green long life but at time of this writing it was still available from Subaru. But knowing Subaru It won’t surprise me if it’s not available before too long.
The Blue coolant is scheduled to be changed every 100k, I believe this to be a very bad idea and suggest it every 60k instead. If you change the coolant in an older model Subaru to the new Blue coolant, I think it’s unwise to believe the service interval can be stretched out to 100k as well, and do not think it’s worth doing. Interestingly enough it appears that Subaru still wants the Conditioner to be put in, I find it odd that it’s not in the coolant itself at this stage.
You should not use aftermarket long life coolant like Dex Cool. I do not suggest any form of aftermarket stop leak.
Hope that helps clear things up a bit and thanks for Reading.