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Old 08-04-2003, 09:14 PM
Registered User
Join Date: Mar 2003
Posts: 18
89 300 E A/C question

Hi Gang! I dont know how many ounces of oil to add to the compressor or what kind to use. My line a/c line burst so i have just changed it out. I took the compressor off, turned it upside down and let it drain for a week. Changed out the drier. Lines all new. I have purchesed Duracool and will give it a shot and report back to the board about how it works. So
1. Do I need to flush the system with some solvents or mineral spirits?? (duracool folks say it works with anything and dont worry)
2. What kind of oil should i add?
3. How many ounces?
4. If I must flush the system with solvent, can i use mineral spirits or should i buy some of the fancy flush stuff?
5. Where do i add the oil or the solvent flush (little funnel down any line?).
6. I assume i take the drier off and solvent flush around it??? In one side and out the other?
7. Where do I attach the evacuation pump? the high side fitting, or the low side fitting?
Thanks in advance,
Capt. J. Alex Whitaker
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Old 08-04-2003, 10:39 PM
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Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
Ho Boy, lots of questions!

First, you need to measure the oil you poured out and replace that amount. Then add 2-4 oz more as you charge. If you didn't save the oil, I think 160 cc is right for R12, but I will have to check.

You did replace the hose set, right? A splice may work, but usually a blown hose will only blow again somewhere else unless you overpressured it. If it was overpressured, you need to fix that, too, or the new hose will blow in the same spot.

If all that is OK, you need to get a guage set. They are fairly cheap -- $50 or so plus adapters. If you are changing to another refrigerant, you will need the proper fittings, there are several (R12, DuraCool/Freezone and R134a are all different).

Once you have the gauge set, you attach the vac pump to the yellow line and open both high and low valves to evacuate. Pump to 29" and see if it holds -- should stay very near 29 to start with, and must be at least 28 after 30 min for leakfree operation.

Big leaks show up fast, but you need to keep the vac to 29" or better for at LEAST 30 min to get the water out, or the vac will drop to about 26 right away. An hour is better, and the bigger the vac pump the better.

Check the vac by closing both valves.

To add refrigerant, close both valves, unhook the vac pump, and hook the can of refirgerant to the yellow hose. Puncture can if using the samll ones, then open the can valve and bleed the line by loosening the fitting at the gauge set ONLY untill it hisses. DON'T loosen any more than that, you will spray liquid refrigerant all over, very dangerous. Let it his for a couple seconds to blow the ari out of the line, then tighten back up.

I usually blow the first can in as liquid into the HIGH side (red hose). I then start the compressor and let the vacuum draw the rest into the LOW side -- a bucket of warm (not hot) water makes this go a lot faster.

If you have a large (20 lb) container, you can blow the entire charge in as liquid on the high side with the cansiter on a scale to measure what is going in.

If you aren't sure DON'T charge it without someone experienced to help, you can easily freeze your eyes with liquid refrigerant, and if you have a small can attached to the high side, it will explode if you ever get much in. Not funny.

1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!
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Old 08-05-2003, 12:39 AM
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Join Date: Mar 2003
Posts: 18
Great, thanks for the reply. I will add 160 cc of oil..........but what kind?? The duracool people say any what kind is best?? I guess i will pour that oil down a line with a tiny funnel. Next do I run the engine and compressor while i'm evacuating or just do it with nothing running?
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Old 08-05-2003, 07:30 AM
Posts: n/a
Your system was designed to run with R12.

You should be aware that Duracool is illegal for use in mobile a/c systems in 17 states plus the District of Columbia.

I will use nothing but R12 or R134 and will not service any car that has anything else in the system.

psfred offered some excellent instruction for you.

Good luck,
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Old 08-05-2003, 01:44 PM
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Join Date: Mar 2003
Posts: 18
Larry thanks for the reply maybee you know

Larry thanks for the reply maybee you know what the best oil is for A/C systems and how to get it in there. I assume you dont want oil in the dryer. Also, do you run the compressor while your evacuating to get more circulation or just do it stationary.

BTW the reason i'm trying duracool is for several reasons. First the last time i had r 12 done professionals evacuated the system and installed r 12 it lasted only days. I felt it extremely irresponsable to be venting r 12 into the atmosphere (besides paying $90 to do it). So when i fixed it myself a couple years ago i used 134. It did not cool adaquatly in our 100-110 degree days, especially when its humid. So i'm gunna slap a duracool label everywhere over the old stickers and give it a shot (r12 is not available without taking some tests or something so using it is no longer an option and I cant afford to pay them to vent it again). I understand that duracool can burn, I have weighed it and since my car runs on gasoline and my engine room is open to the enviorment is on the bottom (i understand that these gasses are heavier than air). I would not feel safe running duracool in a boat or aircraft but in a car I feel it a safe risk, I will also post No Smoking stickers on all seats just in case.
Thanks in advance,
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Old 08-05-2003, 02:38 PM
1991300SEL's Avatar
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Join Date: May 2003
Posts: 497
I'm assuming you've obtained the DuraCool. It's sounds as though you do not have a 609 certification(what you need to buy R-12).

Assuming I'm right, how did you obtain the DuraCooL?

I suppose my point is, if you obtained DuraCool w/o a 609 certification, then DuraCool is not a true R-12 replacement.

Many people buy these "alternate" refrigerants" thinking they are true R-12 replacements. Freeze-12 for example is 80% R-134A, yet costs almost 3 times more than R-134A.

I'm not trying to start another refrigerant war, just wish to say that these "alternative" refrigerants are not always what they are cracked up to be.

The 609 test is only $20-$25. When I took it, the thing was open book with a total of 25 questions. Kinda like taking a drivers license test or in other words, any idiot can pass it.

Get your 609 cert. and buy the REAL thing. The cost of R-12 is far less than trying to swap out systems.

Just my 2 cents.
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Old 08-05-2003, 04:03 PM
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Join Date: Apr 2000
Posts: 459
There are lots of reasons you shouldn't put duracool in your car, so its worth getting the 609 certification. It only costs around $19. If you have confidence in your repairs, once you fill it with r-12 you should not have to touch the system, or "vent" anything for years to come. Airconditioning systems are designed in relation to the refrigerant that will be used, hence they don't work well with non-factory refrigerants. You already discovered this with the r-134a, so it seems odd, after all of your hard work, that you want to put another sub-standard refrigerant in the system. On a lighter note, you indeed can put oil in the receiver. I distribute oil throughout the system when I have it open, and putting some in the receiver/drier is just fine.

'84 300D, 176k
'90 300CE, 166k
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Old 08-05-2003, 04:21 PM
1991300SEL's Avatar
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Join Date: May 2003
Posts: 497
If you believe in what they put in the A/C text books, you drain the compressor and measure what you drained and do the same for the receiver-dryer.

Compressors don't compress liquids very well and that's what oil is. Too much of it can damage your wallet.
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Old 08-06-2003, 02:24 AM
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Join Date: Mar 2003
Posts: 18
Thanks again, getting a cert does sound easy, which might explain the reason that some shops around here seem in adequate. However I am going to give the duracool a shot. I understand it is similar to freeze 12 being a 134 mix. I am curious to find out if it works or not. I guess that it is the consensus that everybody agrees that 160cc is the correct amount of oil to add considering that the lines are brand new, the drier brand new and the compressor empty. Conversion of the system is not a concern since it is already completely empty. I will report back about the cooling. If it does not cool adequately I guess i will be out $30 and have to convert it back to 12.
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Old 08-06-2003, 09:52 AM
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Join Date: Aug 2002
Posts: 179
I also am trying duracool in my F250 diesel. Seems to work okay up to this date. I know from my research into the product that it is a cocktail, mostly comprised of propane (if memory serves, about 38%). When I looked at its thermal properties, it seemed to follow the R12 curves fairly closely, however, if you have leakage, the first thing to leave will be the lower volitiles leaving a mixture that the distributor up here would not tell me what it was.

For your situation, I would use the original R12 lubricants (don't know the quantities). Thats what the compresor and seals are expecting. The actual duracool doesn't care what lubricant is used so its only the original manufactures hardware that may be effected.

Good luck with the experiment. (PS I agree with your point, your running a very combustable fuel....gas. Should you develop a small leak, it should disperse readily. A guillitoned line however may be more hazardous).
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Old 08-06-2003, 03:26 PM
Posts: n/a
Reading this with interest as I am presently dealing with my wifes 107 a/c system.
Jalex, please don't flush out your drier with anything. Install a new one. There is a little bag of dessicant inside the drier that should be absolutely completely saturated with moisture since the system has been open for some time. You won't get that moisture out of there with a 30 minute or for that matter a 30 hour evacuation.
I think we should all respect the recomendations of Larry Bible and psfred who both work with these issues every day. If you do it their way, it will stay working longer and be more trouble free. If you fool around with the quick fixes of Freeze12 et all, it may work for a while, but your car won't be dependable. It's r12 or 134 for me.
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