1993 Eclipse - R12 or R134a?

A '93 is an R12 system. A retro-fit kit to use R134a (or equivalent) requires:

a) Remove the compressor, drain the old oil and replace with r143a compatible, swap the H and L pressure valve fittings. b) replace the drier cannister. c) replace ALL the O rings wth with r143a compatible rings. d) Evacuate the system and see if it holds a vacuum. If it does, recharge with R134a (or equivalent). Note that you cannot just charge up a system without evacuating it first: it won't properly or for long.

Without the right equipment (air driven vacuum pump and gauge set) you can't do d) yourself.

You could do a,b,c and then take it to an AC shop and have the vacuum test done. They will likely want to charge you $200 or so to tell you that there is a leak somewhere.

Note AC shops have to abide by a whole lot of government regulations, which is why they are often outrageously expensive.

For a 93, the most common leak source is the condensor in front of the radiator. This has taken 15 years of road dirt impacts and winter salt. The next likely source of leaks is the hoses themselves. With age and the change of refrigerant, the smaller r134a molecules leak out through the walls of the hoses themselves. The only solution is to have the hoses rebuilt (don't think about buying new ones, $$$$$). I had some done for my 93 last year. Ask around your local A/C shops: many won't do it, but there's usually someone who will. The process requires that new barbed hose fittings be welded onto the existing pipes as the mitsu fittings are odd. The hoses are then crimped onto the pipes.

You might consider the following:

1. Get a new condensor: you probably need one anyway, also the drier cannister. Look on, say, RockAuto.com. Before you order one, pull out the compressor and check it out. You should be able to turn the shaft and feel the pressure on the in/out ports. There should be no (black) oil leaking out the shaft. If the compressor seems faulty, consider buying a new one. I have a decent 93 compressor here in Ottawa, Canada: its yours for the shipping if you want it.
2. Get the hoses rebuilt. Can't hurt and is cheaper than new.
3. Buy an air driven vacuum pump and gauge set. It's about 0 or so. You hook the pump to a compressed air source and away it goes. This is a good option as its about the cost of having the system leak tested once. Rebuilding an old system often takes several goes at finding the leak. The simplest test is vac out the system. The vacuum should hold with no change for at least a couple of days. If there is a leak, its usually pretty clear immediately as the vacuum leaks away in seconds to hours. Hence my suggestion of replacing the condensor.

You can also vac out the system yourself and put in an R134a equivalent.

regards Stewart DIBBS

In the uk, I just use drop in replacement rs24