W124 Aircon Not working

[chris clk320]

Hello All,

I have the diavia AC sysietm in my E220 W124 and its never worked since I have had the car since 2011 never been that bothered its a summer car and usually the windows are open, but in a quest to sort out anything that doesn't work my attention had turned to the AC.

So I had it duly gassed at ATS and it passed and they charged the system, but nothing works doesn't get cold.

So I am starting cold or not actually! in trying to work out what could be wrong I need to know where to start, firstly and what I can check and discount.

ANy hints tips and advice greatly received.

Thanks
Chris

 

[Charles Morgan]

If they gassed it the gas should have dye to trace where it is leaking, so the first thing is for ATS to check that.

 

[chris clk320]

They confirmed there was no leaks, having just googled the issue it looks like the compressor clutch isn't engaging ie the front of the compressor isn't turning.

How I find out why the compressor clutch isn't turning I don't know yet!

 

[Charles Morgan]

The clutch doesn't engage if there's no pressure.

Did they check for leaks after you had it gassed and returned to them or at the time of gassing? If the latter then take it back as all they do is check it holds pressure before gassing, it is not a leak test.

 

[harryandeileen]

Hello All,

I have the diavia AC sysietm in my E220 W124 and its never worked since I have had the car since 2011 never been that bothered its a summer car and usually the windows are open, but in a quest to sort out anything that doesn't work my attention had turned to the AC.

So I had it duly gassed at ATS and it passed and they charged the system, but nothing works doesn't get cold.

So I am starting cold or not actually! in trying to work out what could be wrong I need to know where to start, firstly and what I can check and discount.

ANy hints tips and advice greatly received.

Thanks
Chris

This might be different on your model,mines a c class220 and if the a/c light is on the a/c is off all the other switches are the other way around,hope this helps.

Sent from my E5823 using Tapatalk

 

[grober]

Diavia - MBClub UK - Bringing together Mercedes Enthusiasts
numerous other posts on Diavia A/C

http://www.mbclub.co.uk/forums/search.php?searchid=10380634

 

[chris clk320]

So I have spent a bit of time fiddling about today. Through a process of elimination and jumping the clutch works on the compressor clicks in and out.

I pulled the diavia fuse and relay and gave them a clean on the terminal's and the auxiliary fans now come on.

So I figured it was the hi lo pressure switch, bear with me on this so I jumped the two terminals on the connector and restarted, the clutch started spinning and stayed on then the fans are on and stayed on. This worked for about 1 minute and cool air was coming in.

Then the, which I know now is a pressure vent at the top of the drier started spuing gas and the no I know bright yellow dye. What a mess!

With the pressure switch correctly reconnected When I switch the car on the compressor clutch kicks in and spins up but then stops it will come back on but then go off and will not come back on. Unless I restart the car.

Is this now because I don't have enough pressure? I suspect the pressure switch is the actual problem.
BUT I need to get the gas taken out first before I change that!
Learning a little about my AC stem as we go but am pretty sure its not a faulty compressor.

 

[grober]

Wonder if you have a problem with your receiver drier. Technically when recharging the air con system it should be evacuated by vacccum pump to remove any moisture and contaminants and the receiver drier renewed before regassing [ bit like an oil filter with an engine oil change] I wonder if you have excessive moisture in the system after its been down so long?

 

[chris clk320]

Intresting thought, it would make sense if I have to degass the system and replace the pressure valve that sits on top to replacve the drier. The only problem is that the connections look rusty so may need new hoses etc...
If I could dignose exactly whats wrong I would happily get it degassed and replace these parts

 

[moakesr]

If the system has been without gas for an extended period, then the receiver dryer should be replaced.

As a minimum, it sounds like you need a new receiver dryer and pressure switch, and I would recommend you get the system looked at by an air conditioning professional, rather than someone at ATS who has been trained to push buttons on the automated machine.

The readings on the gauges will tell an AC professional everything, along with a vacuum test and a nitrogen pressure test.

 

[chris clk320]

Hi Richard,

Thanks for your reply, I think you may be right, would the dryer cause the over presuriseing and ejecting the gas out of the pressure outlet ontop of the drier?? I am assuming the pressure release is a safety feature?

 

[moakesr]

Hi Chris,

I must admit I wasn't aware of a pressure outlet, on a typical w124 receiver dryer, there is a sight glass to enable you to see the refrigerant flow, which was a rather unscientific way of judging gas amount when using R12 rather than R134a refrigerant gas.

It sounds like you had a massive pressure build up, or the dryer failed, the high pressure condition would normally be protected by the switches which signal low and high pressure to protect the system from too much or too little gas.

The fact the system actually blew cold air for a short while is encouraging, it means the expansion valve isn't blocked which would lead to a massive pressure build up very quickly.



Sent from my iPad using Tapatalk

 

[chris clk320]

Hi yes
The frion/dye came out of the top of the drier. the drier looks like this one https://www.autodoc.co.uk/hella/944046

and the vent is the outlet with the nut looking fitting and the car AC hoses connect to the threaded outlets and the pressure switch on top?

I have found a pressure switch at £53.00 plus postage? so really need to know if its that before I go spending.

Regards
Chris

 

[moakesr]

Well, what looks like a recessed hex nut at the top of the dryer is where the sight glass was on my W124 with Diavia AC. Has the system been converted from R12 to R134a? It's a different dryer and the pressure switch is different. Does the pressure switch have any colour to the body? Green? Red?

Richard


Sent from my iPad using Tapatalk

 

[chris clk320]

Hopefully some pictures attached

 

[moakesr]

Some install information here http://ftp.hamsk.ru/auto/W124/Conditioner/1MB24398E/Diavia.doc

You definitely need a new dryer, the system is now open to air after the pressure relief/sight glass blew out. The switch was common to a lot of Diavia systems, and is a combined high and low pressure switch, so it sounds like you need one of those as well.

Problem is, you need to invest at least £100 just to make some progress, and there is no guarantee that there isn't something else wrong.

Webasto now supply Diavia spares, the receiver dryer is here http://www.diavia.it/eng_spares.php?categoria=31&sottocategoria=159&marchio=0&id=968

Richard


Sent from my iPad using Tapatalk

 

[moakesr]

You will also need new o-rings and refrigerant oil to join the switch and hoses to the dryer, I would recommend that you leave that to the AC specialist.


Sent from my iPad using Tapatalk

 

[chris clk320]

Yes I am beginning to think it may be a specialist job
Thanks for the link.

 

[moakesr]

It's a shame you are not local to me, I could do everything but recharge it for you. Unfortunately I don't have a F-gas certification, so can't handle the gas. [emoji17]


Sent from my iPad using Tapatalk

 

[Kevy1]

I had my E280 CDI recharged two weeks ago and during that time it got weaker and weaker until blowing warmish air, Kwik fit have today rOW e gassed and said no leak detected so why did it stop blowing cold air??
Does this pre test they do detect air condenser leaks? Obviously it's losing gas
The said run it for a few weeks and they'll have to have their master mechanic look at it and try and find what's the issue?