sidesbk

First let me apologize if I am repeating a thread... the last thing I want to do is annoy the super helpful people on this site. I did search but could not find the same problem.

Problem/history: At the end of last season, my A/C was blowing just barely below room temperature, but still cooling. I added 134a, but noticed it was leaking at the valve. Did nothing else until this spring when I replaced the valve and cap ($30 - of course MB puts the Shrader valve in a proprietary housing). When I swapped the valve, I worked fast such that I stopped the hissing of escaping refrigerant by the tightening of the new housing--the idea being that if there is still pressure in the system forcing refrigerant out, then atmosphere (with its pesky humidity/moisture) could not yet enter the system. I recharged the system to the CORRECT pressure. The system now works as designed on AUTO, but the air blown is not cooled. Compressor is engaging.

Any experience on this one?

Plutoe

You make big mistake-----simply do the fault test and the actual value test(see stickies)----post the data and you will get help---without the tests the replies will be ----forget the test just add more refrigerant or who understands the test any way, just add more refrigerant----bla bla bla

Rich's 97 E420

You may have avoided allowing the air to enter the system but 134a is a blend of a few chemicals that boil/evaporate at different pressures, even quickly venting them to change a schrader type valve will most defiantly cause an imbalance in the refrigerant's mix ratio. find a buddy with an A/C vacuum pump to assure a complete evacuation, then you can recharge with the proper amount.

This is the reason they recommend we add the compound in a liquid form instead of a vapor like r-12, it did not separate and was easy to just top it off a bit.

Although some of there stuff is pure crap, Harbor freight has a inexpensive set of automotive 134a manifold gauges, and a cheep little single stage vacuum pump, have used mine successfully for over 4 years now. But just for myself and friends. Without any issues.

If your compressor is operating it is a must to have a correct charge. or compressor failure will occur.

You might have a stuck damper, vacuum issue?

Can you use the selector arrows and make the air discharge differently,
floor, defrost, vent etc.

hope this helps a little

Everyone has an opinion, lets find the solution

nelbur

Make sure there is no hot water getting to your heater core. Clamping off the heater hose temporarily should be an easy test to see if you A/C improves.