For the 50 years I've been owning and maintaining my own vehicles, I've substituted a quart of blue Rislone for a quart of oil at oil change. It has worked well for me. I've never had an oil-related engine problem and engines have stayed reasonably clean internally.

Stopped at Advance a couple nights ago to pick up a couple quarts of it. Not only did they not have it (surprise surprise) there wasn't even a shelf slot for it. They had all the other Rislone products, but nobody there had a clue what was going on.

Went on to O'Reilly. Same situation there. But at least they knew why. Rislone is discontinuing the original blue formula quart in favor of PINT bottles of what they call a "high mileage" formula. At the same price as the quart bottle of course. Some freshly minted marketing degree had input I'm sure.

OR had two quart bottles left on the clearance shelf. Got them for $1.17 each.

So, if you use Rislone and can't find the quart bottle, now you know. From Rislone website:

 

Sounds like they hired the Bud Light marketing genus.

 

Probably time to switch to a different oil additive.

 

It's funny you mentioned this, because I went searching for Rislone 2 weeks ago and ran into the same issue. I bought the high mileage stuff.

 

Well, I never used Rislone and I've never had an oil-related problem in my cars (old or otherwise) either. You'll probably be fine if you just keep changing the oil.

But yeah, I get it. I have a few "snake-oil" type products I swear by too, and it's frustrating when Corporate decides to "upgrade".