i am going to be charging my AC system within the next couple of days. i will be using duracool (yes, i have read at least one large thread on the pros and cons. i am aware of the safety issue, but that is a risk i am willing to take.) anyway, my question is, how much oil should i put in the system? i have been told 3 different things by 3 different people, all of whom should have the correct info. called the dealer, and he told me 3 ounces. that sounds like not enough. my dad's mechanic told me "about 4 ounces." the duracool guy said something like 6.63 ounces (i don't remember the decimal, and the whole number may have been 7), but he said it wouldn't hurt to put up to 10 ounces of oil in. i don't want to screw this up...can you guys help me out?

ps-> the system has NOT been flushed, however a vacuum HAS been pulled.

thanks

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1985 300D Turbo "Eunis"

Hey,
I believe the 6.6 ounces is a complete oil charge.
It makes a big difference if the system has been flushed or not, what parts have been replaced, etc..

Do an advanced search on AC and search for posts by Leathermang.

Danny

EDIT: sorry I just noticed you said you didn't flush.

The long and short of it is there is no way to tell how much oil was lost so there is no way to tell how much to add. The only way to be absolutely sure is to flush the system and and add complete oil charge.

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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Duracool and other propane based refrigerant products are not legal for use in mobile AC systems in the US. You mention you are willing to take the risk - I assume you will be notifying passengers in your car so that they can also asses the risks of HC based refrigerants and decided if they want to ride in your car?

Invest $15 and a couple of hours of your time to get a 609 certification. Once you have the certification you can buy real R12 on e-bay for very reasonable prices. I recently purchased a half full 30lb R12 cylinder for $90 - I'm betting your Durafool refrigerant will cost more than my e-bay purchased R12.

"The long and short of it is there is no way to tell how much oil was lost so there is no way to tell how much to add. The only way to be absolutely sure is to flush the system and and add complete oil charge."--dannym

Precisely Correct....

Here is the part of the picture which you are not aware of.... and thus you are feeling that you just need to find the " right" person to ask.... We who have studied this across multiple books , Gurus and several years are in the same position you are in right now. The factory gives a precise charge suggestion for the total system. But they don't know how much will accumulate in any particular low spot in the system at any particular time. They do say that if you are simply replacing a part not under the condition of having a leak for instance... that you can simply measure the oil in the removed one and put that amount into the new one and install....
But if for some reason you can not count on the correct amount being in to start with.. and any refrigerant leak can be assumed to have leaked oil at the same time.... puts you into the position of either guessing.... and the problem is that overoiling the system WILL DEGRADE YOUR COOLING ABILITY... or flushing and putting the correct measured amount into a clean system.
No one is holding out on you, or wrong with the answers ... they are giving you pieces of answers from their past experience. I am only repeating what the professional reference books say. We are all in the same boat on this each time we address an AC system. It is frustrating for all of us.

What's even more frustrating is doing the job half assed and then it doesn't work right.

It's easier and less frustrating to just do it right the first time.

Man, I went through so much crap with my old Ford doing it piecemeal. Should have just done it right the first time. Would have saved a lot of money.

Besides JACrouch, you have a whole 3 page thread with the same info that you started before this one. It's all basic stuff with no real easy way out. If you want it to work and dont want to do everything that's necessary then take it to a shop.
trust me on this one, if you don't do it right you'll be doing it again.

Danny

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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AMEN .... if people would only accept that.... so much money and time would be saved ! And sweat... literally....

I read lots of wisdom in the replies in this thread.

I would RUN from someone telling me to put 10 ounces of oil in a system that would require 8 oz. max and has not been flushed. You could end up with as much as 18 oz. of oil. To paraphrase a Steve Brotherton quote: "Not enough oil wears out compressors, too much oil destroys them."

With R12 at $14 a pound, using junk, not to mention illegal, refrigerant just makes no sense to me. Call me an old fuddy duddy, but it just doesn't add up.

Good luck,

Larry, you are an old fuddy duddy.

i appreciate your insights. unfortuneately though, i simply can't afford to buy R-12. the prices you quoted me are not in line with those which i came accross when searching for the stuff myself. i definitely never saw 30 lbs for only $90.
regarding the legal factor...duracool is only actually illegal in 3 states: arizona, texas, and florida. most of the other states have a law against "flammable or toxic" refrigerants. so, if duracool is illegal, then so is R-134A, due to its toxicity.

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1985 300D Turbo "Eunis"

Duracool is illegal in far more than 3 states. I've seen the list. And I know Virginia is on it. A 609 certification cost $15 and takes all of a hour or two of your time.... R12 goes for less than $20 a can on Ebay for the real stuff, be carefull of the soud alike blends.

You sound like you have you mind made up regardless of the numerous threads explaining why blends are not good to use.

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
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Section 609 MVAC Certified
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"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche

You may be an old fuddy duddy, but you're still 100% correct as far as I'm concerned. Saving a few dollars now will cost dearly down the road. I picked up the fuddy duddy A/C mentality from my grandfather, who was a mechanic all his life, and it's saved me from making alot of costly mistakes.

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1982 300D, black w/ palomino leather, 203K
2001 E320, champagne, 105K (Mom's)
1999 Dodge Dakota, squeaky & battered, 142K

You have not read enough of the posts on this forum about AC stuff..

the test for the 609 certification is open book and takes maybe 30 minutes max.... the cost about $20..
That means YOU can then buy R12 on Ebay at the prices quoted by many.... typically about $20 a lb...
You are not equipped with enough facts to argue with us.

It is your car and you can use whatever you want in it...

also, the reason i thought not flushing the system would be ok is because that's what my dad's mechanic told me.

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1985 300D Turbo "Eunis"

If you are going to trust him.. then why ask here ?

I will tell you what I think happened... He quoted you less than the amount of work it was going to be...and decided he could talk you out of it...and save him some loss on his bad quote..

He knows you are leaving the area... and he won't have to deal with any long or short term problems caused by his actions...

Remember this.... when you are dealing with those people... they have things to sell.... WE do not... we are trying to look out after you while you are dealing with those who have vested interests other than yours....

good point

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1985 300D Turbo "Eunis"