are the sealant and dye ... etc are bad for the AC system ? I am old school and I don't believe in that crap, in my old days it was pure refrigerant from 35LBS tanks, if you have a leak go and fix it. and done with it.

They charged him for new Denso compressor, a couple of hoses, dryer, expansion valve, and retrofit charging ports and labor for sure + freon , all of these parts wort $700, people don't call them stealership from nothing. I started having that feeling that the system is flooded with oil, as I charged the system before to get the sight clear, it was effecting the system in a bad way, lower temp from the vents, height/low pressure side going up. but the sight still cloudy.

I am scared to flush, I heard that flush stuck inside and you can't get it out you are done. I am right in the middle, scared to flush, scared to convert to R12 scared to drain. I don't know what to do

70% you're way undercharged. Having recharged many Gen II's, the ideal weight for an empty system in our climate is 42 ounces. Factory charge is ~46 ounces. Roughly 90% of the R12 charge by weight. Lots of armchair experts like to quote hard numbers when converting "because that's what the Internet said". Most of them are also the same ones that ***** about their converted A/C being weak. Charging a converted system is more of an art than a science, you're not dealing with the factory weight of refrigerant specified by the engineers who designed it.

If you're uncomfortable going straight to 42 ounces, add in 36 ounces, park a reliable temperature probe in the center vent, fan on Max, temp wheel on min cold, all 4 doors wide open. Continue very slowly adding gas in short bursts and watching the temperature gauge in the center vent. Keep adding gas and waiting (1-2 minutes) in between additions until the center vent temperature is 30˚F below the ambient temperature (if it's 85 outside, keep adding SLOWLY until you're at 55). If you want to get the charge perfect, continue adding very short gas bursts and giving the system time to equalize between additions until you see no further reduction of temperature at the center vent. You'll find you added 41-42 ounces of 134a.

Having been charging Fords, Hondas, Mercedes, BMW's, Mazdas, Mitsubishis, Chryslers, GM's, and too many others I've forgotten about over the years, I can promise if you charge the system carefully and deliberately, you'll have ice-cold air with 134a.

Your head pressure will be higher than you expect it to be on a modern car. Ignore that. You're dealing with a converted system, the head pressure will be higher at a proper charge. The Denso compressor will handle it no sweat. The head pressure will actually DROP once you're moving and have air blowing through the grille and the system catches up with the heat load in the cabin.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

42 Oz ???? someone was wrong from another thread !!!! OMG I was struggling for 3 years !! I want to take the junk out inside the system (the dye, the sealant) and whatever in there, do you recommend the flushing ? drain the compressor ? I don't know how much oil inside there.

Depending on the system design and BTU capacity, retrofitting to R134a from R12 will be anywhere from 70-95% of the charge weight of R12. The vast majority fall in the 80-90% range.

You can flush the system if you want. While you have it apart, replace every O-ring in the system and use Nylog (blue bottle) smeared on the O-rings. Remove the expansion valve while you have it apart, it needs to come out to flush the system anyway. After you flush, blow everything out with compressed air until nothing else comes out.

When you put the system back together, pump it down on the vacuum pump for a minimum of 1 hour to make sure you have a nice dry system. Keep in mind that the dye will stain the oil residues in the compressor, so when you recharge, you'll still have some yellow dye in there.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I am taking down to compressor to drain, first to see how much oil inside and put POA68, any recommendations on flush brand, also can you confirm the oil capacity in 7.75 Oz. Thanks for the great information

It might already have been mentioned and by itself it shouldn't impact cooling as negatively as you're seeing but it can't hurt to check whether the outside air flap is closed when AC is running.

If you have the same setup as the Gen I (I assume you do since the early Gen II didn't have the passenger side airbag yet) then the way to check this is by either pulling the glove compartment (easier to see)or popping out the little grey plastic oval in the back of it.

Shine a flashlight in the opening. See pictures which show the open flap (lets outside air in) and closed (recycles cabin air -hence colder). The flap is the part with the deteriorating foam on it.

Attached Thumbnails

   

__________________
'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

Thanks, I took the dash out a month ago, replaced all pods, rubber elbows, and checked all flaps functionality before putting back the dash, also I replaced the old thin layer of foam on all of them with black thin felt.

Good work! I hope you're soon to be rewarded with ice cold air.

__________________
'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

Can the Gen II W126 condenser be adapted to a GEN I system, if yes do you think it worthwhile?

__________________
'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

No real preference to flush brands. Buy the bulk liquid and a flush gun that connects to the air compressor, it'll do the most thorough job compared to an aerosol can. You'll need at least 2 quarts to do a thorough flush.

Most of the Denso compressor car take between 7.5-8.5oz of oil. 7.75 oz should be plenty. My preference is PAO68 since it has superior lubrication properties to PAG46 and is not hydroscopic, meaning that if any moisture ever enters the system it will not turn the oil acidic.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

That I do not know. I'd suspect if so you'd need custom hoses at a minimum. By the time you're in that far, you'd be better off to build a parallel flow setup to compensate for the weaker performance of the Gen I A/C setup (and it goes without saying, convert to a Sanden compressor to get rid of the unpolished poo that the R4 is). The Gen II's have a vastly improved system all around.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Lol. To be fair my '83SD did see 34°F (even below) at the vent at minimum of 45mph with outside temps of high 80's low 90's and typical FL humidity running Duracool (hydrocarbon) refrigerant. Of course in traffic/idling, as you note, it would go up to 50°F and more.

Have a can of grinding rocks R4 in my new '85SD giving at best 55°F at highway speeds so it's due for a refurb. Hence my previous question.

__________________
'83 SD, 2x '85 SD
You are entitled to your own opinions, you are not entitled to your own facts.

before and after pictures




https://ibb.co/gMz9WmH

Thank you for the great information !!!!

https://ibb.co/6NpC8Cv