Q: Heater on 1996 Ford Ranger

ac blowing hot air

I have issues with my coolant disappearing very quickly. I have had to refill a whole gallon of coolant within a week. There are no traces of coolant leakage on the pavement or under the car. However, I have had ongoing issues with vapor coming out of the vents whether the AC is turned on or off with an awful chemical smell. (I drive with the windows down). The mechanics I bring this issue up to don't seem to believe anything I have to say and just keep fixing other things that may solve the issue. I am in desperate need of a real solution. I have had to resort to rebuilding an engine too. And get this: now my car shows signs that my oil pressure is low when I am stopped and returns to about 40 when I accelerate. All these repairs with the same coolant issue... Disappearing coolant with no trace of where it has gone. And please don't say "get a new car" in response I would like to hear some good advice please. :) Thank you and have a good day! If you have more questions, I will gladly answer to help with diagnosis.

Blower only runs on "high".