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When I converted my AC System on my 300D over to 134 two years ago, I changed the Receiver Drier. I am using inexpensive Pep Boys compressors which have to be replaced every two years anyway. I am once agian in the middel of replacing the AC Compressor

(1) Should I change the Receiver Driver again? These compressors only last two years.

(2) The system is open to the Atmosphere as of this moment--I ran out of time tonite changing the compressor. Will this deplete the Dessicant?

(3) What factors affect Receiver Drier Dessicant life?

(4) Whats the lowdown on moisture in the System? I know it exacerbates bearing/compressor wear..

Changing Receiver Drier critical to AC success? 1985 300D

http://mywebpages.comcast.net/snow7ice/BENZ.html

Yes, it needs to be replaced for system efficiency and longevity. While you might not think so, as far as the a/c system is concerned, is tremendous amounts of moisture in the atmospheric air. This moisture can not get into (or remain in) the inside of the a/c system because 1) water and air are not compressible (which causes poor a/c performance) (o.k., air IS compressible, but it takes up space that should be used for refrigerant, which is what causes the cooling effect); and 2) the moisture mixing with the oil and refrigerant can create acid, which will damage the inside of the components. There may be other consequences of moisture, but in my opinion these two are bad enough. You need a new drier and a thorough evacuation every time the system is open.

Question: If you intend on keeping your cars for a long time, why are you buying cheap rebuilt compressors. In the long run, and even in the SHORT run, you are spending way more money. Plus, if one of these rebuilt compressors blows up and throws particles throughout your system, you really caused yourself a lot of work and financial expense.

GregS
'84 300D, 176k
'90 300CE, 167k

OK,, just for general info.. and I will do it the way those Dummies books do some of their notes.....

JUST SKIP THIS POST !
DON'T READ THIS TECHNICAL STUFF BECAUSE YOU WILL NEVER NEED IT !

Ok, for you people that don't follow WARNINGS :

We all know that air is compressable... but in the Air Conditioning trade when they say it is not compressable they mean that at the pressures and temps your air conditioner works at it can not be compressed into a LIQUID.

This factor is used to check and to see if R12 is contaminated in this manner :

you pump your refrigerant into a large cylinder, like the size you see oxygen put into for home use. You chill it also.. and since we know exactly what pressure it will produce at each temperature, then you can read on the pressure guage and check the cylinder for the temp you have it at... if the pressure/temp is not the same then something is mixed with your refrigerant. It is put under enough pressure so that your frigerant becomes liquid... and above that will be those things which are NOT compressable in this sense of the word. Then you let some of the other stuff out.. and then let the cylinder restabalize... because the action of letting gas out of the cylinder affects the temp of the contents. Then the next day you check it again and do the same thing until you only have YOUR clean refrigerant in your cylinder.. at which time you can put the right amount back into your refrigeration system.
I TOLD YOU NOT TO READ THIS.