One of the biggest reasons some of us use HC's is because R134A is so hard on the older compressors and to many have been destroyed by R134A when it gets really hot because they cannot handle the excessive head pressure over 100*F! Mine blew so badly, AAPAK told me it was equivalent to having my motor throw a rod while trying to accelerate onto the freeway! There was nothing left to rebuild!

This cost me more than $1000 for a system that gave mediocre performance at best and happened in 110*F degree heat, just when I needed it most! AAPAK is saying they see a lot of this and it's getting worse as time goes by. If the system wasn't designed for R134A, it will prove to be a poor substitute for R12. Nothing has been a great substitute for R12, But in Massachusetts you are lucky enough not to have Envirosafe forbidden in your state. Regardless of what you use, your system should be in top shape for your safety anyway.

Your lucky to get 2 years service out of your compressor in the Sonoran Desert heat and every serviceman at AAPAK has said repeatedly and I quote "Compressors made to use R12 cannot handle the high head pressures of R134A when the temp gets 100*F or higher. How long it will last depends on how often you use it. The older ones made out of iron can usually be rebuilt, the older made out of aluminum are usually turned into scrap metals." End quote.

If you must use R134A, then I suggest you replace your compressor with one designed to handle it or you can take your chances with a refrigerant like Envirosafe. Envirosafe is conditionally acceptable for mobile applications now in Yuma Arizona where the summer can see 130*F! Mobile AC tech's will service your sytem in Yuma county for HC's and the favourite being marketed is Envirosafe because it is the most stable of the HC's on the market. No I don't have any sort of investment stake in Envirosafe either.

This forum is for us Mercedes guys to help each other with our cars! but some on this board exascerbate intimidation like cops when your views conflict with others and it is making this forum distasteful to many. If you have problems with your system, send me a private message. I've been using your refrigerant for years and I have much experience with it and I will do my best to help you WITHOUT THE FLAMING, ok? We can exchange email addresses or something. The unequal pressures in your system are a dead giveaway something is wrong and I suspect a defective part or a clog.

I have no commercial interest in Envirosafe and I would still prefer R12. But unless I can get it in the single use cans, it has been proven at least here in Arizona that bulk containers have a 77% chance of being contaminated or or of such poor quality it is not worth the risk.

to those whom it concerns--

I asked if the pressure i was seeing normal for envirosafe.

I did not ask for an opinion on whether envirosafe is good, bad, politically correct, i had already made that decision having already installed it in my vehicle so please don't use my simple question as an excuse to rant about your anger with others opinions on freon products.

start your own thread and whine away.

Thank you to those who assisted me in trying to answer my automobile problem as posted by me.

PS I did enjoy the all the bullets flying though

OH and lighten up a little, lets just enjoy what we have in common (mercedes automobiles)

No harm meant to anyone--Steve

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85 300d in progress

Couldn't have said it better, myself...........

A few years ago, I ran into a retired Dow chemist and asked that exact question. His explanation was that the molecules are physically larger and (this is my interpretation) and they sort of 'float' on the top.

I didn't buy it then and I still don't.

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Never a dull moment at Berry Hill Farm.