Advice about refurbing my AC system

[Gareth Randall]

The AC in my 1993 Jeep Grand Cherokee hasn’t worked for about 3 years, and in fact the system was completely open to the atmosphere for over a year while I had my cylinder head off. It’s been back together (but non-functional) for the last year, but now I’m getting ready to replace all the components – evaporator, condenser, liquid line, accumulator/drier and compressor.

I want to do as much of the work as possible myself, but I’ll be handing it over to a trusted shop for the final connection, vacuuming, recharging etc.

My question is, how many of the new parts can I install myself and then just leave to be connected up by the shop? Do any of the components actually need to be off the car in order to be filled with oil, hence I’d be wasting my time installing them in advance?

I know that I can put the evaporator in by myself (that’s the single biggest labour cost saving, since everything else happens in the engine bay, not behind the dash). In an ideal world I’d fit everything except the liquid line and leave it all disconnected, with the ports plugged. Does that sound like a plan? Is it safe to install the new compressor and let the belt drive the pulley before it’s been charged with oil, given that the clutch wouldn’t be engaged and so the pulley wouldn’t be driving the internals of the compressor?

Topic

[Andrew Phillips]

If you are installing everything from scratch, you can put all the parts in place and connect all the lines. The shop can then pull the vacuum and install the oil/refrigerant charge. The compressor will be fine being driven ’empty’ as long as the clutch doesn’t engage. Most compressors come with oil in them. Since your car originally had R-12 refrigerant in it, the new compressor may come with oil in it that is not compatible with the newer R134a refrigerant. In that case you will either need to empty the oil out (measure it before discarding!) and flush it real well with something like mineral spirits and then replace with the same quantity of the proper oil. Let the shop know how much oil is in it. Or, maybe you can get the compressor without oil in it at all. Also, some places may be able to provide the compressor with R134a compatible oil installed. You should definitely ask. Putting non-compatible oil in your new clean system will add money to the job if the shop has to clean it out.

[Gareth Randall]

Cool, thanks for that. I’m reasonably sure that at some point in the past, my AC was converted to R134a – certainly, the info sticker on the radiator crossmember specifies R134a, and the oil that leaked from the compressor when I had it out was flourescent green.

[EricTheCarGuy]

I believe you may find the information here helpful. Good luck with your referb.

http://www.ericthecarguy.com/faq/solving-automotive-hvac-problems

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