Quote: Where did "we" learn this propane / acet "trick?" Is this being taught in some mechanics school? Is it in some manual / book you bought? I've never heard of this before, but as a guy who used to service HVAC, including nat gas/ LP/ oil heat, I'll guarantee you that if you do this enough, you'll regret it.
Better step back on your rant. Propane was once used to set carbs up. It was an authorized mopar service procedure. Properly used I see no problem un using it for a vacuum leak. A running motor is going to burn it not deposit it in the crankcase. There is a lot you obviously do not know.
This is true, it was used but not injected into the crank case. It used externally around carbs, and manifolds much the same as starting fluid is used today, but it was not pressurized into an enclosed area of an engine such as the crankcase/oilpan area.
