Subaru SOA635071 OEM Coolant System Conditioner - USE or DON'T USE?

[Slow Car Sport Mode]

So. I believe I found this particular coolant, I should post the SDS in the other thread but. Yes it is manufactured in Illinois for Subaru and it is this:

That, and the basically 100% new coolant application.. very simple question: Should I use and add the Holts Rad Weld a.k.a. this stuff in the engine? Or is the complete remanufactured short block and heads with Six Star MLS gaskets enough to alleviate that concern!!

Review states:

Because (non-turbo) Subaru automobile engines have what is called an, "Opened Deck," design, head gaskets can be prone to weeping some. (The decks on the turbos are not entirely opened, OR entirely closed. And yes, you absolutely SHOULD be using this conditioner in those turbo engines too!) This "coolant conditioner" prevents a weep that will soon resolve itself if given the chance, from developing into a larger LEAK, requiring expensive service. It is an eloquent solution that has allowed the engineers to produce an amazing opened deck (and semi-opened deck) power plant that truly IS a piece of engineering art. (At least, to a geek like me!)

 

[JayhawkRoy]

I used the cooling system conditioner in a 2003 and 2011 2.5L engine with good success. Both went 150K+ miles without a head gasket issue.
The coolant price seems overpriced, but I haven't bought any since probably 2013.

 

[SubieRubyRoo]

It doesn’t hurt anything. It was recommended for use by Subaru all the way til the last EJ rolled off the line; I’d use it anyways. I always use it in every EJ I service.

 

[cptbarkey]

I use it every drain/fill on Subarus. its cheap, cheap insurance and also specified in a few Subaru manuals, but its not required. Be sure to follow directions, don’t pour it directly in or it will clump up.

 

[slacktide_bitog]

On an EJ, use it

 

[Trav]

The OE Coolant is fine, this is also good and when added to a gallon of distilled water makes 2 gallons of 50/50.
With a new short block, new bolts and six stars HG there is no point in the sealer, that may have helped with the original composite HG but not with the MLS. In an old engine with original or replaced HG with only the heads being surfaced and not the cases then sure use it.

https://www.autozone.com/antifreeze-radiator-additives-and-windshield-wash-fluid/antifreeze-coolant/p/peak-antifreeze-coolant-asian-blue-concentrate-1-gallon/720575_0_0?spps.s=5018&cmpid=LIA:US:EN:AD:NL:1000000:AFR:19355622364&&CATARGETID=120054150001286072&CADevice=c&gclid=EAIaIQobChMIt8_c5Pm0gAMVQfvICh0QKQzSEAQYBiABEgJCMPD_BwE&gclsrc=aw.ds

 

[dkryan]

Hopefully, the HG issues referenced above were resolved before the 2019 2.5L Outback was manufactured?