Help: How do I depressurize AC on truck?

I have a 1991 Mazda B2200 Pickup truck (with Air Cond) with bad piston rings. I took a good engine from a 1987 Mazda B2200 with no AC. My questions are:

How do I de-pressurize the AC so I can remove the engine? I have to de-pressurize right?

Can I put in the NON-AC engine without modifications?

OR

Can I add the AC somehow to the NON-AC 1987 engine?

Any help would be greatly appreciated thanks

Reply to
atari
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Take it to an automotive AC shop and have them recover the refrigerant. They should be glad to do it if it has R12 in it.

Yes.

Use the AC bracket from the original engine, and any pulleys etc. that are necessary. If you decide to keep the AC you might be able to unbolt the compressor from the engine and replace the engine without opening any refrigeration line.

Reply to
Mike Walsh

If your going to remove the lines YES. BUT you can more than likely unbolt the compressor and move it out of the way enough to get the engine out.

As long as it is the same size engine with the same electronics.

Yes, unbolt the needed brackets from the engine your pulling and mount them on the replacement engine. Then bolt it back together.

Reply to
Steve W.

Coolant recovery: Talk to a mechanic (or perhaps the auto shop program at a local vo-tech college) about getting it out in the approved manner. Intentionally venting R-12 to the atmosphere is illegal (it's bad for the ozone layer) besides which the stuff is getting rather dear and you might need the same amount of it later. They might be able to work with you on repressurizing the system after you're done.

Since you're taking everything so completely apart, if you're going to do an R-134a conversion you'd never have a better opportunity; though some people have their doubts about how much cooling you'll really get from what I'd guess to be a smallish (i.e., appropriate for a compact car or a truck cab) system that wasn't made for R-134a. Be prepared to blow out everything with compressed air and to just replace the receiver/dryer or accumulator, whichever you have, unless you are fully confident that the system was in really good shape and blew ice cold before the engine went.

Realistically, if it was a kid you'd be buying it a graduation present pretty soon... and again, if something is marginal, this is your best and easiest chance to fix it.

Doing the deed after R-12 capture: Transplanting the A/C system to the new engine might be easy or difficult, depending on the layout of the engine bay and accessory drives. If you're lucky, they're basically the same engine and how to do this will be obvious. You'll also be spending some time in the Jacques Cousteau position changing the heater core and control panel. You might, or might not, also need to beef up the cooling system. A good way to start would be with repair manuals for both years of truck -- look for differences between A/C and non-A/C models of 1991.

An issue irrelevant to A/C but possibly important in your future is how to get a 1991 truck smog-checked with a 1987 engine. This might be disallowed; a bit bureaucratic but technically not much trouble; or easy; or a complete non-issue, depending on the differences in emission standards between the engines -- and highly dependent on where you live.

Best of luck,

--Joe

Reply to
Ad absurdum per aspera

Well, I've said dumber things before my second cup of coffee. Since the recipient vehicle is the one that presently has A/C, you've got the dash controls, heater core, radiator, etc. made for it.

Whoever brought up the possibility that you might get the engine out and leave the A/C unbroken has a good point. This is possible on some vehicles (the longer the hoses rather than hard tubing, the better; the more room, the better) and is worth at least visualizing. Doing this without kinking or snapping anything expensive is where a helper or two really comes in handy.

As for bracketry etc., it'd be great to have two engine stands so you can put the old and new engines side by side and see if a lightbulb comes on; although it's easier to sort out in the car with fore-and- aft rather than transverse engine layouts. (My old Camry is starting to leak power steering fluid, and fixing it might involve a trained octopus or the liquid metal guy from Star Trek or something.)

--Joe

Reply to
Ad absurdum per aspera

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