Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

LinkBack Thread Tools Display Modes
Old 01-14-2004, 01:22 AM
Registered User
Join Date: Feb 2003
Location: Burbank, California
Posts: 184
92 300D 2.5 turbo =Propane in AC+more

The car has just had new engine and is almost completely restored. I purchased the car in Sept. 03.

The AC was a not as cold as in some of the other cars that I have owned. I took it to a Radiator shop that I have gone to for 15 years.

The tech hooked up two gauges and told me that it was holding pressure. He then put a machine that looks like what the ups drivers have. It reads what is inside of the system.

Results= Beep Beep Beep with a red flashing led. The system has R12, R134 and propane. The beep was to warn of flammable mixture. Propane!

1.Why would someone put propane in there?

2. Tech did not want to mess with the car after that. Where do I go to get rid of it?

3. He said to clean it out. Put a new dryer in it and to bring it back to evacuate the system and to recharge the system with R-12.

Any recommendations?

Thank you

Nick Mendoza
Reply With Quote
Old 01-14-2004, 03:04 AM
dmorrison's Avatar
Registered User
Join Date: Dec 2002
Location: Colleyville, Texas
Posts: 2,694
You probably have a blend snake oil freon. Freeze 12, Durafreeze, etc,etc. Someone figured they could get the system to work with the "new freons". Many "new freons" use Propane as part of the freon blend.
Your system will work better under R12 even though its expensive or R134 if its originally designed as a R134 system.
Now you have a problem. This is the problem with all the "new freons" Finding someone who can work on the system. Not because of the type freon used but because your AC Tech does not want to contaminate his system. Freeze12, or any new type freon, in a R12 or R134a system makes the hole recovery system contaminated and the container of freon, trash. Now as a certified 609 AC Tech he cannot release freon into the atmosphere. So how do you get rid of the freon in your system. This is the problem with not using the R12 or R134 that 99% of the shops are set up for.
Who ever did the conversion did it illegally. Each freon type must have the official fittings installed on the hoses to prevent cross contamination. Since your AC man was able to connect to your system the fittings are probably R12 or R134 fittings. Even if not a 609 certified tech, Federal law determines conversions of AC systems and what MUST be done to the fittings by anyone.

So were do you go from here. Either go to the person or dealer you bought the car from and find out what freon is in the system. You can continue to use THAT freon, after changing the hose fittings and posting the changes to the system as per law. But who can you find to work on it, that is the problem. Or you will have to find someone who can evacuate the system, another problem. Then flush it, Replace the reciever dryer and go with either R134 or R12.

go here and see if you can get some advise.

The best reason not to use alternate freons is your example. You don't know what is your car and you can't find a tech to service it because he want to protect his equipment, thousand of dollars worth. So your screwed because someone did a conversion on the cheap.

Again find out what is in your cars system.
You will have to find a shop that can evacuate your system. Let it be known that releasing it to the atmosphere is illegal, $10,000 fine per event. You will have to completely flush your system, hoses, condensor, evaporator, compressor ( actually a oil fluid cleaning don't use a flushing agent) and replace the reciever/dryer. All this because you don't know what oil is in the system. R12 uses mineral oil and R134 uses PAG or POE oil. The 2 oils cannot mix and cause neither oil to stay in suspension. If both oils are in the system your compressor will fail due to a lack of proper oil in a mist state. Then your rebuilding your system again within a year or 2. Re-oil the system with the appropriate amount and kind of oil for the freon used and fill it with R134 or R12 ( the new synthetic oils are good for both R12 and R134 but you don't know what's in there). Check that the expansion valve is R134 compatable if going with R134. Being a 92 it should be compatable with R134 but make sure if going that way.

Good Luck

1970 220D, owned 1980-1990
1980 240D, owned 1990-1992
1982 300TD, owned 1992-1993
1986 300SDL, owned 1993-2004
1999 E300, owned 1999-2003
1982 300TD, 213,880mi, owned since Nov 18, 1991- Aug 4, 2010 SOLD
1988 560SL, 100,000mi, owned since 1995
1965 Mustang Fastback Mileage Unknown(My sons)
1983 240D, 176,000mi (My daughers) owned since 2004
2007 Honda Accord EX-L I4 auto, the new daily driver
1985 300D 264,000mi Son's new daily driver.(sold)
2008 Hyundai Tiberon. Daughters new car

Last edited by dmorrison; 01-14-2004 at 03:58 AM.
Reply With Quote
Old 01-14-2004, 11:24 AM
Registered User
Join Date: Jun 2000
Location: Plano, TX
Posts: 2,525
Propane is actually a pretty good refrigerant. There are blends of various hydrocarbons out there, being sold as replacements for R-12. I refer you to the endless flame wars which have taken place here on the board during the heat of the summer. As to whether propane is dangerous, I would say it certainly adds an element of risk. I personally don't think the additional risk is terribly significant relative to all the risks one already assumes driving an automobile, but that's just my opinion. I should note that I'm using a refrigerant blend in my old car which contains 4% butane. Of course, that's not enough to make it flammable - the oil in the system is much more likely to catch fire in an accident.

As to what you have to do - get your system cleaned out. Call around to see if you can find a garage that can/will recover the "junk" mixture. You may or may not be able to find one that can do so. It's illegal to vent "refrigerant" to the atmosphere, so that's not an option. (Oddly, this includes the propane, even though you can vent all the barbeque gas you want...) Don't event think of removing the black plastic caps and depressing the schraeder valves to release the refrigerant. Not only is this illegal, but it's dangerous - there is always the risk of frostbite when working with refrigerants, even on a hot summer day!

You probaby want to flush all the oil out of the system and refill it, as well. Given the mixture of refrigerants, you probably have a mixture of various kinds of oils within the system. This will require some disassembly, and removal of the compressor, but isn't terribly difficult.

After that, button it all up, replace the dryer, add oil, vacuum, and recharge. Should work like a champ.

- JimY
Reply With Quote
Old 01-23-2004, 03:26 AM
Registered User
Join Date: Feb 2003
Location: Burbank, California
Posts: 184
Update on AC

Problem fixed.

I took the car to get the combination of gasses cleaned out.

I replaced the receiver dryer.

Went back = Tech flushed the system.

Filled it up with R12 and the AC is coooollllldddd.

If you have an AC problem DO IT IN THE WINTER! The guy told me about the first hot day. He has so many people that he has work for two weeks.

Thank you

Nick Mendoza
Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 09:12 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page