QS "15,000 mile" motor oil

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May 25, 2005
An empty oil can I saved from 1980:

"It will permit extended drain intervals of up to 15,000 miles or once a year, whichever occurs first."

I never tested it that far

Quaker State by the late 70's had developed a serious reputation in a lot of circles as being a sludge potion. I can personally attest to a few tarred engines being the result of QS.

My understanding, at that time, was that QS was trying to save face by offering this new magic elixer that didn't sludge up. Not only that but make the dubious claim that it was so good you just about never had to change it! Nobody really fell for it, but some of us former QS users had an oil that we could use for regular 3k oil changes and not worry about it sludging up. I only used it a few times and wasn't really impressed due to the price (then, like now, I could get the Havoline a whole lot cheaper) and if I remember correctly it wasn't much cheaper than the M1 was.

I didn't see it again shortly after QS went plastic, around 84 or so.
Even now we aren't seeing 15k mile oil changes with dino oils. It's hard to beleive it sold much due to the horrible reputation that a 10w-40 had due to the high viscosity improvers of that grade, and the sludge potential of pennsylvanian crude.
There is a MIL-C rated oil for trucks in india, single weight SAE 40 made by the government owned Hindustan Petroleum which claims 18000Km
I have an old copy of Popular Mechanics from 1983.....it has an add for this exact type of oil in cans like this....doesn't mention anything about 15,000 mile OCI, though.....
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