Air Con on ML270

[Joderest]

Hi all, not sure where to post this.
The Ml270 has sprung another surprise on me, in recent warm weather, air con not cold, just cool.
It seemed to clear the screen quickly in the winter, so thought all was ok.
Am i correct in saying that the system has some sort of pressure switch, which would detect no gas and turn system off, giving a red light in the controls ???
It could be as simple as a regas needed, but as i have no service details or anything, do not know if it has been re gassed, ever !!!!.
any advice would be appreciated before i book it in for a suction down and regass if no leaks
Thanks in advance

 

[Joesoap17]

It does have a pressure switch, not sure about the red light?
But at £50 for a re-gas and pressure test it is worth getting it done first.
All air con machines do a test to see if it can hold vacuum, and if it passes will then proceed to re-gas, usually a no pass at vacuum stage does not incur a charge, or that is the case at Kwik Fit, its one of the few jobs I will get done by them as its not operator dependant.

 

[AltonAnt]

There is a Groupon offer at the moment for a regas at ATS for £30.

 

[Joesoap17]

Not sure how groupons work but at that price got to be worth a try!!

 

[Joderest]

thanks, its been suggested i use my Icarsoft MB2 and see if system has pressure on live data, i did not know it could do that, i will have a play tomorrow and see what it says, if i can find the air con part on the machine.

 

[AltonAnt]

thanks, its been suggested i use my Icarsoft MB2 and see if system has pressure on live data, i did not know it could do that, i will have a play tomorrow and see what it says, if i can find the air con part on the machine.

Look for AAC I think which is at the bottom of the list on i980 at least.

 

[Dec]

See what you get with a meat thermometer stuck in the drivers side air vent, should be about 5°c or 42°f

Dec

 

[Joderest]

Lucky enough I have a small electronic meter that also has a temperature probe.

 

[Trickythemerc]

Look for AAC I think which is at the bottom of the list on i980 at least.

MB11 will show you aircon pressure in the system.

 

[190]

There is a Groupon offer at the moment for a regas at ATS for £30.

Do you have a link for this because I can't find it on the Groupon site

 

[OneForTheRoad]

pretty sure today was the last day 4 it.

 

[AltonAnt]

Could some kind soul post what pressure a well functioning AC system reads with a diagnostic tool please or know what the spec pressure should be.

 

[AltonAnt]

I have seen a reading of 12-14 bar mentioned.

 

[Joesoap17]

seems about right if a little high read this:
AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - Automotive Air Conditioner Problems, Part II

 

[Trickythemerc]

At 24c ambient temp you should typically get Low side 35/40 psi or 240-310 kpa Hi side 150/170 psi 1034-1172 kpa

 

[AltonAnt]

Thanks guys.
I wasn't sure if my gauge was working correctly and I didn't want to over-charge it. It is currently at 6 bar according to iCarsoft so the gauge appears to be correct at about 1/2 full.

 

[Joderest]

Ok, done a few test that have left me even more muddled.
Engine running, out side temp 20. Temp at vent 13.
MB2 gave some odd readings on air con bit
Battery voltage 1.11v
Refrigerant pressure 40 bar
AC compressor .off
Engine fan . Off
In fact all values were off.

If I selected an engine speed graft then it would show a slight increase when Aircon turned on, and a slight decrease when turned off.

I am still none the wiser

 

[Joesoap17]

Look don' overthink this, 98% of the time a re-gas is all thats needed!!

 

[Joderest]

Yep, that's going to happen very soon

 

[Joderest]

Well, i have been told today that our good old Government has applied a levy to the gas used for air con, a bottle of the gas that cost £70 last year is now in excess of £300, do not know how true that is but i had to pay more than i would have done in the past, anyway.....
The guy that does my aircon, checked it for me and said pressure was very low, when the machine did its readings, there was "135" of gas, should be "750". he sucked it down, it all held pressure well, recharged it all with correct oil and gas, all working well now, have 4c at vent (very cold).
His thoughts were it had never been recharged, and was surprised that it still retained some pressure. I will see how it goes. Cost went up from £40 last time he did one of our cars to £70 this time due to increase in cost of the gas.
He cannot understand how the other outlets do it so cheap, he also spent an hour doing this as he checks over the whole system.
At this time, problem resolved.