2012 Mercedes GLK 350 - A/C Cooling problem

Friendly format provided to inquire about automotive a/c systems.
Archived Forum

Moderators: bohica2xo, Tim, JohnHere, Dougflas, HECAT

forumoto
Posts: 3
Joined: Fri Sep 18, 2020 9:58 am

2012 Mercedes GLK 350 - A/C Cooling problem

Postby forumoto » Fri Sep 18, 2020 10:04 am

my ac blows hot on freeway, Cool in town what could it be.?.and Cool in park..?

Compressor has been changed yet still...

Thanks
Dougflas
Posts: 346
Joined: Mon Apr 18, 2016 6:10 pm

Re: 2012 Mercedes GLK 350 - A/C Cooling problem

Postby Dougflas » Fri Sep 18, 2020 2:09 pm

Start looking at the metering device. If possible, tape a gauge set onto the windshield and give us the readings.
forumoto
Posts: 3
Joined: Fri Sep 18, 2020 9:58 am

Re: 2012 Mercedes GLK 350 - A/C Cooling problem

Postby forumoto » Fri Sep 18, 2020 2:54 pm

Metering device? You mean the manifold gauge or what?
Dougflas
Posts: 346
Joined: Mon Apr 18, 2016 6:10 pm

Re: 2012 Mercedes GLK 350 - A/C Cooling problem

Postby Dougflas » Sat Sep 19, 2020 2:31 am

forumoto wrote:Metering device? You mean the manifold gauge or what?


Negative. I am speaking of the TXV or orfice tube. There are the devices that allow refrigerant to flow into the evaporator.
Al9
Posts: 223
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: 2012 Mercedes GLK 350 - A/C Cooling problem

Postby Al9 » Sat Sep 19, 2020 3:15 am

The expansion device is a TXV. This, and the compressor's solenoid valve, work together to regulate refrigerant flow across the A/C loop at all times.

Refrigerant pressure readings alone will provide little or no information, because this is an electronically regulated variable displacement compressor system. Real info comes from the PWM compressor output's signal, but this requires expensive tools to analize.
forumoto
Posts: 3
Joined: Fri Sep 18, 2020 9:58 am

Re: 2012 Mercedes GLK 350 - A/C Cooling problem

Postby forumoto » Sat Sep 19, 2020 6:12 am

Expensive tool like which type? Are you thinking about scan tool? I have autel scan tool. Which can analyze the lice data pid of the A/C module and Engine Module, all that matter is the sensors to select for this info to display and record.
Al9
Posts: 223
Joined: Tue Mar 10, 2020 3:26 am
Location: Southern Europe

Re: 2012 Mercedes GLK 350 - A/C Cooling problem

Postby Al9 » Sat Sep 19, 2020 7:09 am

Oscilloscopes and very expensive scan tools.

That's if you want to troubleshoot and not just toss random parts at it hoping for the AC to behave itself.

Ensuring that the system is leak-free and charged with the correct amount of refrigerant is always recommended as the first step whenever cooling acts up.

Return to “Automotive Air Conditioning Forum”