My ac is only blowing outside temp. air. The compressor is working and the climate control wheel is ok also.heater functions as it should.Compressor hoses are not getting cold.no change when adding freon.any ideas?thanks

What's the high-side pressure when doing this?

I do not know.I am using just a home charge method,a can of freon straight to the low side.Untill this year,I have added 1 can of r 134 per summer,and although the a/c is no match for the southeast ga heat at midday, It has always cooled enough to make the humid mornings and evenings a bit more enjoyable.All components are original.

Good old death cans.

Take it to a shop to get the excess refrigerant drained. More is not better and do not add a can every year unless you've verified it actually needs it. If it actually looses that much in a year, you've got a bad seal that needs fixed.

If there is some other problem...and you just add R134a ...which may have worked in the past... you have the potential of getting too much refrigerant into the system...and since the AC works on the principle of having low and high sides so the phase change from liquid to vapor can draw out the heat.... overfilling is the kiss of death for the AC system... it greatly overworks and/or does not produce cool.... if this occurs..
You have ' gotten away' with your procedure up to now.... but now you need to step back and do a more thorough evaluation of what is happening or risk more damage and more expense.

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

A bit of advise on the home charge, instant fix a/c cans available from unaware high school kids at the parts store. It's your car, your eyesight. When a hose explodes in your face, your will understand.
Buy a good set of gauges, learn how to read/use them and read/learn how a/c functions and fix the problem correctly.

__________________
DO IT RIGHT THE FIRST TIME, DON'T BE A HACK
Political Correctness is NOT part of my vocabulary
and finally FIGHT CRIME...SHOOT BACK

'82 240D Stick
'85 300D Auto
Drove my first MB at age 16 1960 300SL W190

Go to http://www.id-usa.com/ to see the FAQs. They know what they are doing and produce a lot of A/C kits for an average DIY.

If you have one of their charging hose with a pressure gauge then you cannot go very wrong. It is color coded and just follow the instructions and wear eye protection gears. Use common sense.

Green then you need R134a.
Blue band then it is fully charged.
do not charge if it is above blue.

The charging hose should NOT fit the high pressure side unless someone mess it up.

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

I had one of those fail on me. The hose came right off of the barb. Fortunately, it was aimed away from me, but the refrigerant coming out of the low side port covered the car in oil by spraying between the hood and the windshield.

Im still paranoid from having the upper radiator hose let go all over me Thursday night.. I think i'd rather be frozen than get 2nd degree burns from overheated coolant if I had to do that all over again .

Me and my dad got to watch the high side on a 10 ton unit explode a while ago it's pretty scary to know what such innocent systems can do to you until you really see something like that happen.

Safety glasses look stupid, but missing an eye looks way worse IMO.

__________________
http://i106.photobucket.com/albums/m...73378_30-1.jpg

Thanks for all the info.what has me wondering is why it is not cooling period.shops always want to tell you how many parts you need to replace.Guages are the way I should go.One more tool to add to my 250+does it ever end

You are looking at it wrong...
This is an opportunity to acquire more tools/ big boy toys.....

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/showthread.php?t=156207&highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

It starts with a simple two-valve manifold set and explodes from there, if you let it. I tend to let it. I just ordered a $160 Robinair sealer remover for working on friends' cars.

You guys are right.I have a 72 300 sel to do also.thanks for the support