I'm redoing my a/c system and keeping it R12. The original R4 compressor is currently in the car and has the typical front shaft seal leak. In addition the system has a pressure switch leak, expansion valve leak and some hoses that need reworking.

I'm going to take the compressor from the wrecked car and use that since its 3-1/2 years young. It was a new R4 compressor and the system in the old car was retro fitted R134. I think the oil in the old system was Ester (could be wrong).

What would I use to flush the old compressor of ester oil in anticipation of going back to mineral oil? Can the compressor be turned in order to completely flush, while out of the car and without the clutch being engaged? I have read that perhaps I just need to flush it with the oil that will end up being used with the R12. A couple of complete flushes back and forth?

Also.....don't use flush fluid or thinner in the compressor?

Is there a better synthetic oil to use in place of the standard mineral oil.

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

You will be okay if you just pour in some mineral oil and turn the shaft by hand some to circulate it through and then pump and pour out as much as you can get. You are right, DON'T use any flushing agent in the compressor.

I'm assuming you are flushing the entire system. Make certain that you get ALL of the flushing agent out of the system. After that put a few ounces of oil in several places as you put things back together to distribute a total of 6 ounces of Mineral oil throughout the system.

If you're not flushing the entire system, and since it has always been R12 and the compressor didn't scatter, you shouldn't really need to, Just put a few ounces of mineral oil in the compressor. Mineral oil will work great in an R12 system. There are some folks who will want to sell you a magic oil, but mineral oil will work great.

Put on the filter drier last after everything else is in place and sealed up. This will minimize the contamination of the new r/d. Pump it down a long time since the system has been opened.

Good lu

We went to put the old compressor (3-1/2 years young) in the NEW car. The pulley/clutch assembly was slightly bent from the accident.

Pulled it off. You would not believe how difficult it is to buy just the clutch and pulley in Los Angeles. Of course I left the compressor at my buddies and didn't write down the compressor model number. I have the pulley/clutch assembly in the trunk. These R4's came in all different configs, so you really need the model number.

Also the old compressor is the flush style port and the new compressor is the stepped style port. Didn't have the special seal set you need for the stepped port.

Of course this was on Sunday and neither Napa or Autozone has the seals (or the pulley/clutch).

A/CKits didn't have it in stock either.

Worse case, I have to go to a GM dealer.

Plus we are having a heat wave out here and I have a dark colored car. I'm hot and cranky.

__________________
84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

I second Larry's post. I will tell you my experience. I didn't pull the expansion valve last summer after a compressor failed from a 134a retrofit. My "new" compressor off my wrecked car only lasted 1000 miles.

This time I pulled the expansion valve so I could flush the evaporator and all the hoses. I used mineral spirits first since it is cheap. After thinking all the black oil was out of the condensor and evaporator I used some 141 flush. A great deal more "black oil' came out of what I thought was a flushed system.

You can not flush enough. I knew better last time, but took a short cut by not pulling the expansion valve and I had to pay for it.

The Duraflush or 141 flush is $$$$$ which is why I used the mineral spirits first. If you are going to do it, I recommend doing it right once.

New R4 new dryer and 2.2 oz (W116) of R12. It is now working great!

Good luck and be cool

__________________
1980 300SD Manganese Brown Metallic Clearcoat 248k
1979 300SD White 148 k
1984 300D Silver project car for daughter
1982 300D wrecked
1980 300SD 310K not running

There is a company in Orange,Ca. called California Air on Enterprise St. They specialize in auto A/C Parts.
Don't go to Hose Man and have hose's made. They made them 2" too long.
Good Luck.
Charlie

The original compressor didn't seize. But at 20 years old, I suspect its life is limited. With R12 at $100, today I ordered a new R4 because I couldn't find the f**ing pulley for the 3-1/2 year new compressor. We flushed the system anyway. Its currently sealed up and tomorrow we'll install.

New R/D, new expansion valve, new R4 compressor. New discharge hose directly "before" the condensor. A rebuilt manifold hose and a rebuilt suction hose. All new O-rings. I went with the NEW discharge hose because it was only $37 from the dealer. The other 2 hoses are big $$ new and I noticed that the Euro has effected parts costs. That manifold hose was $305 last month. Its now $386.

__________________
84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

I would like to do the same on my 87 300D. Seems the evaporator sprung a leak and the system is holding ZERO charge. I plan on taking this project slow and easy - I'd hate for the NipponDen$$$o compressor to bite the dust...

Eric,
Sounds like you will be in good shape.... remember that the orings are to be lightly coated with new refrigerant oil.... or that higher viscosity stuff ...and that it comes in two colors .... to match the frigerant you are using..... refrigerant oil to be put into the compressor should be left sealed until the last minute..... at the time you are about to start the vacuum process.... almost impossible to get moisture out of the oil .

Speedy, Hope it is just the lines to the Evap or something else which is leaking.... Evap is the worst case on many cars in terms of replacement labor.

For those that may not be aware of it....
MB wrote a factory shop manual for the AC on the 123 cars.....

" Can't flush too much" this is very very true....

However, a part of the picture which is missing is the fact that the flush machine shown in the manual recycles/filters the flush fluid... so you can dissolve/catch lots of stuff with an initial flush...then use clean flush and do it again.....

By ' recycles' I mean it runs it through your car parts over and over again.... I suspect most DIY persons are using flush in a ' full loss' mode... just pushing it through one direction and either catching it... or just blowing it out on the ground.... which does get expensive on the flush liquid fast.... and may cause people to not flush as well as the system may need....

Ok this is helpful, but to the basics.

I have a 1980 240D. The compressor was declared dead by an A/C shop. Dirty front shaft is one clue, no pressure in system is another.

I have ordered a new R4 compressor and have been looking for a deal on a drier and expansion valve.

Sounds like I need to flush system first. What do I use, where do I find it, and how do I go about it.

What about seals and valves? I intend to go to r134. I can let the A/C shop do it if I need to.

Final fill up will be at A/C shop, after he does leak test. I want to have as much done as I can B4 I take it in.

__________________
69 220D not running
79 240D parts car
80 240D Beater runs everyday
81 300TD temp disabled cooling problem
82 300SD sweet

Question for Eric .
Who rebuilt your hoses?
And how much was the charge?
Charlie

Flash123, you need to do a search for that to get you started on the right path.... then if you have more specific questions ask them.... Mucho material already posted on that stuff...
Also go to aircondition.com...
and if you have any really tech questions call Trey at Carlisle auto ac... one of the sponsors on that aircondition site...