I made the page a seperate entity so it will load faster.

Tell me if you all think is works better on your system.

I should now load much faster!

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

opps now it will load faster.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

Hi all, great thread.

Just curious about R-134a.....does it have an aroma?

I have noticed what might smell close to a strawberry or similar aroma that I think may be associated with my AC....I resently bought my w124....and the AC wasn't cold. So I recharged it....Everything was good for a couple of weeks. Then basically it gave up due to low freon. So i recharged again Saturday...two days ago. It's working again. I'm thinking I have a leak. Maybe near the evaporator.... because I noticed the aroma this AM. However the system was OFF and so I left it off. I know a real leak probably doesn't care if the system is on or off. It wasn't hot enough to need the AC and my driving time to work is pretty short. Any aroma may have been partially due to the fact the car was closed up all night and held the various gases. Then I start the car in the morning and perhaps got a whiff of the collection which accumalated over-night

More information as I go through this period of evaluation should be expected in the near term if the system is actually leaking.


Thought I'd leave a question to this excellent forum in the effort to get a early response.

Thanks in advance,

Ron_of_orange

1992 300ce w/83k

No 134a does not smell like any type of fruit. Get the system leak checked bacause 134a does cause testicle cancer, so you dont want to breathe it.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

Same goes for blends like Freeze-12, which is 80% R134a.

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

All refrigerants are "blends" Yes the beloved R-12 is "blend" of many different chemicals. I believe you mean Freeze 12 is an azetropic mixture as is many refrigerants used in daily life. Near azetropics mixtures are also mixtures of other refrigerants but must be charged in as a liquid due to fracterization of the refrigerant in vapor form. Near azetropics also have a temperature glide or will change state at 2 different temps. The new 410a is one such refrigerant.

Inquiring minds want to know.

__________________
1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

Your splitting hairs here.
A blend is considered any refrigerant made up of 2 or more chemically different liquids.

Danny

__________________
1984 300SD Turbo Diesel 150,000 miles

OBK member #23

(\__/)
(='.'=) This is Bunny. Copy and paste bunny into your
(")_(") signature to help him gain world domination

An issue with blends is that the lightest components are likely to leak first. What is left in your system is an undefined component which does not perform as an efficient refrigerant. So a system charged with a blend that has leaked cannot be topped off to restore cooling but must be emptied and recharged completely to restore efficient cooling.

This may have been posted before but this thread is so ridiculously long that it is unlikely that anyone will read the whole thing.

R12 is CCl2F2. Like most refrigerants, it is not a blend. My point was simply that Freeze-12 is mostly R134a.

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

http://www.epatest.com/manual609.html#_TOC_8

Refrigerant Blends and System Retrofitting

Widespread research has been going on for replacements for CFC-12 and many other refrigerants. Refrigerant blends have entered the market and are currently being produced by many chemical companies.

Refrigerant blends are mixtures of refrigerant that have been formulated to provide a similar pressure/temperature relationship to the original refrigerant. Blends can be HCFC based, HFC based, or a combination of both. The HCFC-based blends are only interim CFC replacements because of their non-zero ODP. The HFC-based blends will be the long-term replacements for certain CFCs and HCFCs until researchers can find single refrigerants to replace them.

Many blends also use a flammable component (such as propane, or butane) as one of the components in the blend. Table 2 contains a list of common refrigerant blends, which have at least one flammable component, and are available on the market for stationary HVAC applications. Not all of these refrigerant blends have SNAP approval for use in automotive applications. Table 3 contains a list of the Motor Vehicle Air Conditioning Substitutes that have been approved for use in Motor Vehicle Air Conditioning (MVAC) applications. The refrigerants listed in Table 3 as "ASU" are acceptable for use in MVAC systems, while the refrigerants listed as "UNA" and refrigerants listed in Note 1 (that have not been submitted for SNAP review) are unacceptable for MVAC use. This SNAP approval does not mean that the alternative refrigerant is compatible with the materials (or lubricant) used in the MVAC system or that the performance of the unit will be similar. SNAP approval only means the environmental effects of the refrigerant are acceptable and the refrigerant has been tested to be non-flammable as blended and therefore the EPA will allow the use of this refrigerant in an MVA application. As part of the SNAP approval the refrigerants are tested to verify that the refrigerant as blended is not flammable. The EPA has made it illegal to use flammable refrigerants in motor vehicle air conditioning systems. Each potential new refrigerant must be tested according to the American Society of Testing Materials (ASTM) E-681 testing method to determine flammability. In addition to testing the refrigerant itself, if a blend contains a flammable component, the EPA requires leak testing to ensure that the composition does not change during a leak and become flammable.

The SNAP approval also includes a requirement for unique fittings to be installed on the high and low side service port of the system being retrofitted with the alternative refrigerant as well as unique fittings on the refrigerant cylinders which contain the alternative refrigerant. The unique fittings are part of an effort to minimize cross contamination. Table 4 lists the fittings for the SNAP approved MVAC refrigerants. Only SNAP approved refrigerant substitutes, that have been specifically approved for motor vehicle use, can be used in MVAC systems.

Some refrigerant blend manufacturers have chosen trademarks that may give the impression the "New" refrigerant is a drop-in for R-12 and have even incorporated the "12" as part of their name (FREEZE-12 for example). However using any substitute refrigerant requires as a minimum that the high-side and low-side service ports be changed to the SNAP designated fittings (Table 4) and the system be re-labeled to indicate the replacement refrigerant contained in the MVAC system. That means there are no refrigerants which can simply be charged into an CFC-12 or HFC-134a system without any hardware changes! There may also be other changes necessary such as new seals, hoses, lubricant, and additional safety devices. The EPA has several publications available on their Internet Site ( http://www.epa.gov/ozone/title6/609) or available from their HOTLINE (800-296-1996) which discuss compressor replacements, retrofit procedures, sources for retrofit training, and common Questions and Answers.

http://www.epatest.com/manual609.html#_TOC_8

Even though there are replacement blends on the market that will supposedly replace R-12 with minimal retrofitting, Mainstream is not aware of any automotive manufacturer to this date that has approved a refrigerant blend for an R-12 system. R-134a is recognized as the refrigerant of choice for new mobile air conditioning systems. There has also not been any single refrigerant or blend that is a direct drop-in for R-12 in automotive air conditioning systems. There is always the need for some retrofitting of the system. Finally, most blends and their lubricants are not compatible with the existing R-12 system and will require separate service equipment. Recharging a blend is also quite different, you must always recharge as a liquid.

There is a lot of misleading advertising concerning blends... many start with using " 12" in their name to give the impression it is compatible with R-12...
Then there are also dealers which will makes claims which leave out the necessary steps for a proper long life working changeover. Sometimes the non intuitive route is actually the cheapest and best in the long run... much reading and studying is necessary to find that out most of the time on something as complicated as our situations with these old MB AC systems existing in the modern world.

i definately concur.if your thinking of retrofit.study study study.

__________________
michael cole 1980 300SD gone now but not forgotten,87tdt,90 300te 4matic 95 e320 wagon

just dropped by...read responses since my initial post. My situation remains the same. AC still blowing 38F. If I have a leak...it's slow or subject to external circumstances...all of which I haven't discovered as of yet. I didn't notice an aroma today. yesterday and the day before would be a yes.

I read on a different thread about MOLD being a possible problem. I believe a drain pan and lack of good ventilation may have been the culprits which allow mold to form.

Perhaps someone has some experience along this avenue?

MY 1992 used to live in a cooler climate....Bay AREA (calif). Just a guess, but my vehicle may not have had a lot of useage when up north. Now it's in South Calif....and the summer temps are a bigger concern.

Question: Mold collection in a cooler climate now evidenced when exposed to a higher ambient.....possibility?

Thanks all

ron_of_orange 12:06 PDT

"Perhaps someone has some experience along this avenue? "

If we had... it would be in the archives and accessed by hitting the search button at the top of the page... that is the fastest way to find most anything because otherwise you have to wait for the ones that know a particular answer to come on line...and then hope they will type out the answer again knowing it is already in the archives...
We have posted extensively about mold in the evaporator especially...