Last fall I removed the A/C compress in my 88 Duke Fiero. The only reason I removed it was to remove the water pumps housing, with removing it I found out that the high pressure switch was broken off but I am sure the compressor is still good. My question is what velocity and how much PAG oil should I use to fill up the compressor? I lost some oil when compressor was removed, the P.O. had R134 fittings on the old R12 dryer I have a new dryer and orifice tube to install also new o rings.

I removed the compress hose assembly and blocked the lines to prevent bugs or dirt getting into the line under the car. Anything else I should do for a reliable A/c set up?

Jim

[This message has been edited by FieroJimm (edited 04-08-2009).]

Hey Jim

Not sure on the viscosity but I would let the compressor drain - then add 4 oz to the compressor when you reinstall it and put the other 4 oz in the dryer. I would take the lines off of the condensor in front and under the hood and flush them with an A/C line flush solvent. It's hard to flush the condensor because they have a twin internal tube design - you just push any debris from one tube to the other. If you believe the system to be clean you are ok. If you are not sure, you may want to look at replacing the condensor too.

Once you get everything flushed and reassembled, you will want to pull a vacuum on the system. This pulls out the moisture and will show you if you have a leak. If you can't get it to pull vacuum and hold it, there is a seal or something leaking somewhere. Make sure that when you put it back together that you use new orings. The amount of vacuum you can pull on the system varies with altitude. There is a table on PFF that will lay this out for you (gotta search for it). I am at 4500 feet and can only get about 25psi of vacuum. I let the vacuum pull on the system for a few hours at least - the longer the better. Then I shut the vacuum pump off and let it sit for awhile watching the vacuum gage. If it holds, you are ready for charging if not you have a leak.

Now having siad all that, you can hold a vacuum and still have a leak - it only shows up under pressure. On an empty system, I will use the refrigerant that has the dye in it for the first can. If you pulled and held vacuum, you can usually get the system to take the whole can without the car running and the system on. Right after I get that first can in, I go around the car looking for leaks. If there are no leaks, I go ahead and start adding more with the engine running and system on.

There are some great threads in here that will guide you step by step through the process if you are going to do it all yourself. It's pretty easy if you have all the right tools and a set of gauges. The first Fiero I did was before I was a member on PFF. I went to autozone and bought the instructional DVD. It is a pretty good guide but it is not specific to the Fiero. Read all the threads you can. Here's a good web site for A/C - lots of good info here too. Good Luck!

Pat

http://www.autoacforum.com/

[This message has been edited by katatak (edited 04-08-2009).]

Thanks for the info Pat. There is different PAG oils 50,100,150 not sure if they are the same or not. Hopefully I can find more info online

Thanks again,

Jim