2006 Legacy hot air on driver side, cold air on passenger side.

[Pinegrovesubaru]

An old time mechanic recommended Bar's Leak to me thirty years ago as a way to prevent miscellaneous leaks and to lubricate the water pump bearings.
I have been using it at every change of antifreeze on every vehicle I have had since 1980. I never had this problem on any vehicle, including the 95 Impreza and the 2002 Legacy.

The 2002 Legacy was consuming antifreeze slowly, about a pint a month. I know the history of head gasket leaks on Subaru's, but didn't want the time and expense of doing the heads.
So I added a second bottle of Bar's Leak.
Then I added a third bottle of "professiona"l Bar's Leak.
Then I added a bottle of Subaru Blue Goo. After a month the leak stopped. I know it is hard to believe but the heater and radiator are working fine. This was about 50,000 miles ago. The engine just turned 203,000 and besides a small oil leak it is doing fine.

What is amazing to me is the 2002 had three bottles of Bar's Leak and the it never affected the heater coil. The 2006 had one bottle of Bar's Leak and it blocked the coil. Weird.....

[Dookie]

Very interesting, I'm glad you were able to find the problem and fix it. That is a new one for me.

[TurboLegman]

Originally Posted by Pinegrovesubaru

An old time mechanic recommended Bar's Leak to me thirty years ago as a way to prevent miscellaneous leaks and to lubricate the water pump bearings.
I have been using it at every change of antifreeze on every vehicle I have had since 1980. I never had this problem on any vehicle, including the 95 Impreza and the 2002 Legacy.

The 2002 Legacy was consuming antifreeze slowly, about a pint a month. I know the history of head gasket leaks on Subaru's, but didn't want the time and expense of doing the heads.
So I added a second bottle of Bar's Leak.
Then I added a third bottle of "professiona"l Bar's Leak.
Then I added a bottle of Subaru Blue Goo. After a month the leak stopped. I know it is hard to believe but the heater and radiator are working fine. This was about 50,000 miles ago. The engine just turned 203,000 and besides a small oil leak it is doing fine.

What is amazing to me is the 2002 had three bottles of Bar's Leak and the it never affected the heater coil. The 2006 had one bottle of Bar's Leak and it blocked the coil. Weird.....

As an Oldtimer, I can tell you, the Bars Leak was good back when we were driving '40 Fords (wish I had my old one now) and '37 Dodges, but the heater cores used to be copper. Not now! The crap used for todays heater cores are just that, CRAP! Don't use the old additives that we used to use! When I was a kid, black pepper was a popular additive to stop leaks around a waterpump shaft and saw dust was used in the rear ends to stop a roar! Get my drift! Don't do it!

[TSi+WRX]

How does Bars Leak compare with Holt's Radweld?

The reason I ask:

http://www.subaruforester.org/vbulle...houghts-65712/

"Subaru Conditioner."

^ A topic of persistent mystery!

[o0Dreamless0o]

I hate to necro a thread 8 years old but I've had extensive problems with this issue. I've changed actuators, rebuilt actuators, heard of people putting new heater cores (never attempted it), watched videos of flushing, with and without cleaning solution. with only sporadic success.

I believe I found the issue today.

Most cars that have this issue usually have one thing in common, recent head gaskets. Moreover, people tend to blame a clogged heater core.

If you look at the way the heater core is positioned in relation to the feed and drain hoses, it is possible to mix the lines up (because when they look "right" when they are incorrectly attached to the motor side) When hooked up in this way, it never lets the air purge properly from the heater core.

I've had my 2008 for about 6 months now and it had no passenger heat when I bought it...I was so sick of this problem (from my 2007 but love my Legacy's) so I literally plugged up those vents, much to the wife's dismay.

Today while swapping out a bad reman'd rack, I swapped those hoses for ****s and giggles, instant heat from the passenger on startup....instant...fiery...glorious heat. that car was partially warm, but that passenger heat has been ice cold from day one.

dual zone or manual controls, doesn't matter, same heater core.

I hope this helps anyone in the future who suffers from this. I myself live in New England so heat is really really nice lol!