Aircon on, but air doesn't feel cold
 

(E320 CDI W211 2007)
I think it needs air conditioning refrigerant refill, but I thought it would have told me in the display if so?

Is it easy to clean and refill?

Aircon switch lights on.

A/C seals leak up to 2 oz/ yr. Figure out how old yours is times 2 for how much "normal leakage" you have and you will know about how much needs to be added. Unless of course you have a real leak.

I was at a workshop. Both the cold and varm had a good pressure.
He got the temp down to 6 celcius degrees by measuring the temp at the fan-opening inside the car.

He said that there was enought refrigerant on the system - because it could cool down to 6 celcius degrees.
Nothing else was done.

The next days I tried setting the temp at 12 celcius degress or LOW and the fan at full power - no cold air :-(

Can I check if the aircon compressor is running?

Might be your issue:

https://mbworld.org/forums/e-class-w...rol-valve.html

Even at 6C you don't know the SCFM of the air movement. With no air movement a ice cube could get 6C but in a 50 mph wind it couldn't.

The car should have been outside in sun, all doors open ac on max high and doors/windows open, blower max high and still have 6C. If it was inside in shade doors closed a/c on auto the 6C doesn't mean the freon isn't low. The pressures in the system will tell if it is low. The standard way to verify freon is to read high / low side pressure with system at max out put. A thermometer just doesn't give enough data.

No cold air at all.
I've just felt the black tube in the engine room. Not cold - not water drops. Just "outside" temp.
The warm alu-like tube "outside" temp. Not warm.

I can't feel any difference in the 4 zones. All normal temp air.
Does that excludes the heater control valve?
And no cold/warm side/zone - I think that excludes the duovalve?
What's wrong? -Do you think it's low on refrigerant and therefore turn off the compressor?

To properly diagnose A/C issues I need to know what your pressures are. The gauge readings need to be at 2000rpm with A/C on max cool. The outside temp will determine the correct pressure readings.

The most basic question is, is the compressor clutch engaged and spinning the compressor?

If the pressures are good then you have an air flow problem. Hot air from heater core could be mixing with cold air from the evaporator. There could also be other air flow problems. But without accurate pressure readings it's just guess work.

Hi! The mechanic told me that the pressure on both the cold and warm side was in the good/best end of the interval. Can't remember the "numbers". That day the cold side/tube WAS cold... and it haven't been since.

Haven't felt cold air since the testing (can pressure be on/off? maybe something that turns the compressor off?.)
The cold side/tube in the engine room isn't cold.
Belt is spinning/running.
Since the cold side isn't cold, what does that tell?

It sounds like the compressor isn't engaged. The belt spinning doesn't mean the compressor clutch is turning. You should be able to view the actual clutch turning when the A/C is on, and not turning when the A/C is off. There will be a loud "click" when the compressor clutch engages.

If the pressures were good the other day it's unlikely that all of the R-134 has leaked out. I would check the A/C fuses first. It still sounds like the compressor clutch isn't engaged.

Thanks. Where in the car can I find the A/C fuse? or fuses?
Someone told me that I can't see if the clima compressor runs or not, because it's variable and not has an on/off as and old one.

Yes, the compressor is clutchless.

Thanks for all your answers!

The A/C LED (red) is on/lightening - does that mean that the clima compressor aren't dead for sure?

Can someone describe where I should look after the fuses and which "name"?
(maybe there's more than "A/C" or something like that)?

I apologize. I wasn't thinking clima system. You won't hear an audible click since the compressor is always engaged.

But even more critical in this instance is that you have to know your current a/c pressures when the system is operating. It still sounds like there is no refrigerant flow in the system since there is no temperature differences in the hoses. You didn't mention if the condenser fans were running when the system is on because that is a good clue for refrigerant flow.

Beyond that, check all the fuses if you have to. Use a volt meter to make sure you are getting battery voltage across them. If all the fuses check good it's probably time to seek a professional.

>>It still sounds like there is no refrigerant flow in the system since there is no temperature differences in the hoses.<<
-No refrigerant flow - does that mean low refrigerant?

>>You didn't mention if the condenser fans were running when the system is on because that is a good clue for refrigerant flow.<<
-What are the condenser fans? Please describe - then I'll check it.

-I Can see some fuses behind the batteri in the back for the car. But is it these fuses? Where can I find which number is which ?
Can't find anything about fuses in the manuel.

I had a problem last year. AC would blow and nothing come out at all...Since car was still under warranty, it was the regulator that is below the glove compartment in the passenger footwell. It is a common problem with these cars.

Nothing come out at all? -okay no air at all?

My vents/fans blow very well but not cold air.

Test on low side showed 2 or 2,5 bar (can't remember).
Test on high side showed 15 bar.
Tells that pressure is good.

When pressure is that good, does that mean that system aren't leaking?

Only 50g was on the system.
The 50g got off and then 950g on. Vacuum was testet for 45min with no error.

Just can't understand there was only 50g back with still good pressure.

About 6 times since I've owned the car, when I start it, all of the functions on the LCD say they're working, but the AC is completely silent and no air is blown out of any vent. I play with it for five minutes, turning it on/off, adjusting settings, etc, and it finally comes back on and works normally. This happened twice during last week's heat spell, but there are no codes associated with it. Were these your symptoms as well?

Your pressures are good so refrigerant flow is not your problem. The refrigerant system is operating within factory specifications.

You cannot accurately measure how much refrigerant you remove with a standard a/c machine. That is not what they are calibrated for. They are calibrated accurately for how much gas and lubricant they install into the system.

Your problem is with air distribution inside the car. I can't diagnose further since there are many possible causes. It's time to find a professional and get the car properly diagnosed and repaired.

I think it's cooling after it was filled up to 950g refrigerant.
How much should it cool temp down to? And how will you check/test it by yourself?
Got it under 6 c. degrees. (same as last check with only 50g on). But it feels colder this time.

Is it possible to have only about 50g on the system without a leak - what do you guys think?

I'm confused. It's cooling now?

Around 5 degrees C is normal. Depending on outside temp, solar load, rpm, and fan speed.

To test the total cooling efficiency of your system simply park your car in the shade, stick a thermometer into a center outlet, set fan speed on low, recirculate mode enabled, windows up, and with engine rpm around 2000-2500 rpm. Allow the system to run in this state for approx. 8-10 minutes. This will give you the maximum cooling capability of your system. Anything around 36-42 degrees Fahrenheit (2.5-5.5C) is very good.

Still confused. If it's been getting to 6 degrees why did you think it wasn't cooling? 6C is obviously cold.

No...50g is low, so if it truly had only 50g of refrigerant then you have a leak. But once again, how was that amount measured? I already explained that a standard a/c machine will not give you an accurate measure for how much refrigerant is removed. I don't understand your concern if the car is cooling properly now. Did the person that charged your a/c previously find a leak?

There seems to be a disconnect between what you said originally and what you are saying now. If you are getting air from the vents at 6 degrees C then you are obviously getting a cold a/c.

this was exactly what happened to me last summer. It would blow cold air with a/c red light on. Then nothing, no air. Then a few minutes later it would all of a sudden blow really fast and go crazy. Took it in and it was some relay part that was known to fail. Its a $40-$50 part and didnt look hard to install, but since car is still under CPO, got it done.

Yes it's working now so far. My concern was that the mechanic also got the temp down to 6 c.degrees the first time I was there. 2 weeks before and 2 weeks after I haven't felt cold air.
Maybe it was the last refrigerant back in the system pushed around in the test..

2nd visit (2 weeks after): 50g got off. Measured by the "vacuum"/test-machine. It wrote 50g in the display. I don't know the uncertainty. The machine didn't find errors/leaks. He didn't put some test-fluid on it.
Now 950g was put on.
Under 5min it got under 6 c.degrees. It also feels cold, when I drove home (didn't after first visit).
And it's still working.
If it's leaking will it normally be empty within days ? Thanks.

This amount is on a vehicle basis. I have two MB -- a 2003 C320 with 200K miles and 2006 E320CDI with 105K miles and neither one has ever had a thing done to the A/C system. I checked the center vent temp on my 06 E320CDI last week while driving down the highway with a digital thermometer and got reading consistantly below 40 degrees F. That was a middle of the day with full sun and outside temperature + 95 degrees F. I recently checked the E320CDI with the the gauges and both high and low pressures are where they should be according to the temp and reference material I was looking at: Best recall the low was 35-40psi and high was 150-160 psi at 90 degrees F outside temp.

So the point is you need to have the tools and knowledge to properly diagnose any A/C system (mobile or fixed). I would not top up a system based on a predicted 2oz a year loss. If I followed that logic my 03 C320 would be overcharged.