Head Gasket Seal in a Bottle; Up or Down?

I know we talked about this type of product recently but I'm curious as what kind of luck folks have had.

Background

My 11 Outback cracked the upper radiator pipe last week. I replaced the radiator but I'm getting a whiff of coolant. The car is also using a very small amount of water (maybe a pint in 40 miles).

I pressure tested the system (note my tester is from HF) and it won't hold more than 7-8 psi.

I plan to keep the car long term, it's currently at a 140K, I've had it 9 years and since it's a 6 speed manual. 

It's something I was willing to pour into a '01 Grand Marquis with a milkshake in the radiator. 

It had a bazillion miles on it. We figured if we got another year out of it, we'd be way ahead of the game in terms of what we paid for it a few years prior. 

The only maintenance we ever did (or were ever gonna do) was changing the oil. If anything else happened to it or the bottle didn't work, it was going to the junkyard. So we weren't concerned about what it did to the internals. 

It lasted another 2 years or so before we sold it, still running. 

Tom1200 said:

I know we talked about this type of product recently but I'm curious as what kind of luck folks have had.

Background

My 11 Outback cracked the upper radiator pipe last week. I replaced the radiator but I'm getting a whiff of coolant. The car is also using a very small amount of water (maybe a pint in 40 miles).

I pressure tested the system (note my tester is from HF) and it won't hold more than 7-8 psi.

I plan to keep the car long term, it's currently at a 140K, I've had it 9 years and since it's a 6 speed manual. 

How did you jump straight to headgasket?  I've had hoses fail in the darnedest places and only leak when pressurized, and only leak enough that it evaporated.  I would want to find the missing water first, especially since you just did the repair.  There's no way to do a radiator without a baptism in coolant, so coolant cooking off and the system burping air could still be happening.

Headgasket in a bottle - sometimes it works, sometimes it doesn't.  It's a last resort thing.  I'm 50-50 on it working, personally.

I've found they work pretty well. They'll seal pretty much every small leak or opening in the car. 

Note: That's not always a great thing. Beware of clogged heater cores and such. But for a beater with no alternatives, go for it.

In reply to Tyler H :

You would be correct I don't know for certain it's the HG but I'm lining up my options and hence my question. 

In reply to Tom Suddard :

Definitely a last resort.

Tom1200 said:

In reply to Tyler H :

You would be correct I don't know for certain it's the HG but I'm lining up my options and hence my question. 

Maybe I'm a raging optimist, but I'm betting it is something more mundane than a HG, even on a Subaru.  Good luck!

It's great when it works, when it don't you are out a few bucks and you have to do a teardown anyway so to me it's worth a shot for a beater. 

Might as well use the official stuff...

In reply to obsolete :

Didn't even know that stuff existed.

Before going head gasket-in-a-bottle, how about testing for the presence of combustion gasses in the cooling system?

Amazon link, not a canoe:

https://a.co/d/aDVlSYF

In reply to thewheelman :

Perfect I was looking for that.......

UPDATE:

So the car appears to be fine...............it used progressively less and less water over the course of a few days. My assumption is that I didn't get all of the air out of the system.

I also suspect my HF pressure tester doesn't mate well with the radiator or it's more of a guide than a gauge. 

The coolant smell has also gone away.

UPDATE part duex.....

It started to overheat in a traffic jam........sigh.

Is the fan working?

In reply to Purple Frog (Forum Supporter) :

Both fans work.........first thing I looked at.

Dye test it

And then yeah, last resort and it's still working on my 2.5. I bypassed the heater for a while just in case, but hooked it up later and it still works.

K seal is my go to for coolant system in a bottle repair.

Drain half a gallon out, mix it with the sealer and dump back in.

In reply to P3PPY :

How many miles after the sealer?