That is very unfortunate.

It is illegal to topoff an r-12 system with Freeze-12 (or anything other than r-12, for that matter). The system must be labeled as converted, and fit with the special SNAP Freeze-12 fittings. What you got was probably a full evacuation and recharge with Freeze-12, though $60 sounds low, even for that.

Freeze 12 is an r-134a blend with 80% r-134a, and it is said to be compatible with R-12 mineral oils due to additives. This compatibility is widely disputed, however, and may only really work well with specific types of mineral oil. Many who advocate the stuff still suggest a taking all of the steps one would for a r-134a conversion, including POE oil.

The other big 'claim to fame' is that Freeze-12 provides cooling characteristics more similar to r-12 (superior to r-134a), such that retrofitted systems will not lose their efficiency. This is also widely disputed.

It is said that the cutout pressure should be lower for Freeze-12 as well. The more you dig, the less of a 'drop in' it becomes...

While it is "EPA approved", the EPA SNAP approval process only considers environmental and health factors, not technical performance.

What you needed was a simple 1 pound topoff of r-12, perhaps $30-40 worth of gas.
I would be very unhappy if this happened to me.

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1986 300E 5-Speed 240k mi.