2017 G350 w463 Aircon

[Mavman350]

Hi All,

Reaching out regarding Aircon on my G350, the car has 180 000KM on the clock and the cars Aircon seems to lose blowing pressure, the air is cold and i've topped up the gas. But it seems to be more a thermostat issue or similiar.

Has anyone here had similar issues or advice on how one can get this fixed?

Based in Pretoria, any help would be appreciated!

Thank you!

 

[Leovans]

Have you replaced the pollen filter?

 

[Gwagon7]

The evaporators are a known issue in the G350's and replacement means the dash has to be removed. I am not sure who would be a good provider to do this in the Pretoria area but even the recommended provider in Cape Town caused onward issues by not replacing the dash correctly in my vehicle. A reputable vehicle aircon service co will be able to test to see if that is in fact the issue.

 

[Ernst]

Have you replaced the pollen filter?

If the Air is cold and you lost blowing Pressure this would be your most likely scenario. Easy and cheap Job.

 

[johanmaree]

If the pollen filters not being the culprit I will recommend the Aircon guys in Eastleigh, Edenvale. They have redone the complete AC in my 350 and gave a one-year warranty. Very good workmanship.
Tel 011 4521602 "Auto Aircon"

 

[Mid]

I have a similar issue with my G 350. The aircon works fine for a few hours drive and then then suddenly drops blowing pressure. After switching it off for say 10-15 minutes it works well again. My research so far.
1. Evaporator Freeze-Up

• Cause: In high humidity or prolonged aircon usage, the evaporator coil inside the HVAC system can freeze over. This blocks airflow and reduces cooling efficiency.
• Symptoms:
• Weak or no airflow from the vents.
• Aircon works again after the car is turned off for a while, allowing the ice to melt.
• Solution: Check the system for proper refrigerant levels and ensure the evaporator temperature sensor is functioning correctly. The thermostat might not be cycling the compressor properly, causing freezing.

2. Overheating of the Air Conditioning System

• Cause: Prolonged use of the aircon in extreme heat, especially at low vehicle speeds or in traffic, can lead to the condenser overheating.
• Symptoms:
• Reduced cooling when driving slowly or idling.
• Cooling returns after a break or higher-speed driving.
• Solution:
• Inspect the condenser fan to ensure it is operational.
• Clean the condenser of dirt or debris to improve airflow.

3. Compressor Overload or Clutch Issue

• Cause: The compressor may have overheated or temporarily shut off due to thermal protection mechanisms.
• Symptoms:
• Warm air from vents after prolonged use in hot conditions.
• Normal operation resumes after a rest period.
• Solution:
• Check for proper operation of the compressor and ensure refrigerant levels are adequate.
• Inspect the compressor clutch for wear or failure.

4. Refrigerant Level Issues

• Cause: Low or incorrect refrigerant levels can lead to inefficient cooling and compressor cycling issues.
• Symptoms:
• Cooling is inconsistent or insufficient during long usage.
• Works fine after a restart or when ambient temperatures drop.
• Solution:
• Perform a refrigerant pressure test to confirm levels and check for leaks in the system.

5. Blocked Cabin Air Filter

• Cause: A dirty or clogged cabin air filter can restrict airflow to the vents, especially when the system is under heavy demand.
• Symptoms:
• Weak airflow from the vents, even though the fan is audible.
• Solution:
• Replace the cabin air filter and clean the ducts.

6. Faulty Blower Motor or Resistor

• Cause: A failing blower motor or resistor may cause weak airflow, especially at higher settings.
• Symptoms:
• Noticeable decrease in airflow volume despite the fan running.
• Solution: Inspect and replace the blower motor or resistor if necessary.

 

[JJVDMZN]

Also check the solenoid control valve, my G350 A/C worked perfectly on the 1st start in the morning but as soon as I switched it off and on again it would blow cool instead of cold air. The valve is located on the compressor and eases the pump into action stopping the sudden drop in rpm's like the A/C's of yesteryear.

They replaced the valve and it was fixed.

Regards,

J.J.

 

[Mid]

The A/C solenoid control valve (also called the refrigerant control valve or expansion valve) plays a crucial role in regulating refrigerant flow and system pressure. If it malfunctions, it can cause the A/C to stop cooling intermittently and then work again after a break.

How the A/C Solenoid Control Valve Works

• It regulates the flow of refrigerant into the evaporator based on cooling demand.
• It is electronically controlled and adjusts the compressor’s operation for efficient cooling.
• If it fails, refrigerant flow may be too high (overcooling/freeze-up) or too low (weak cooling), leading to intermittent performance.

Symptoms of a Faulty A/C Solenoid Control Valve

1. Intermittent Cooling:
• The A/C works fine for a while but then stops cooling or blows warm air.
• After the car is turned off and restarted, it may start working again.
2. Weak Airflow or No Cooling:
• The A/C may struggle to maintain cold air even when the fan is running.
3. Erratic Temperature Fluctuations:
• Cabin temperature may cycle between too cold and too warm.
4. Refrigerant Pressure Issues:
• A faulty solenoid valve can cause incorrect refrigerant pressure, which may show up in a manifold gauge reading.
5. Ice Build-Up on the Evaporator or Refrigerant Lines:
• If the solenoid valve sticks open, it may overcool and cause evaporator freeze-up, restricting airflow.

How to Diagnose a Faulty A/C Solenoid Valve

1. Use an OBD-II Scanner (iCarsoft MB V3.0 or Equivalent):
• Check for any HVAC system error codes related to refrigerant flow or compressor control.
2. Check Refrigerant Pressure (With A/C Running):
• Low pressure on the high side or fluctuating pressure may indicate a faulty valve.
3. Listen for the Compressor Cycling:
• If the compressor cycles too frequently or not at all, the solenoid valve may not be regulating refrigerant properly.
4. Inspect the Refrigerant Lines for Ice:
• Ice on the refrigerant lines suggests a potential stuck-open solenoid valve, leading to overcooling.
5. Check Electrical Signals to the Solenoid Valve:
• Using a multimeter, test for proper voltage and ground at the solenoid control connector.

Possible Fixes

• Reset the HVAC System:
• Sometimes, recalibrating the HVAC system using a scan tool can restore normal operation.
• Replace the A/C Solenoid Control Valve:
• If confirmed faulty, the solenoid valve needs to be replaced (it is often located on the compressor).
• Check Refrigerant Charge Levels:
• An undercharged or overcharged system can affect the solenoid valve’s operation.
• Inspect the Compressor Control Circuit:
• A wiring or relay issue can also mimic solenoid failure.

 

[Mid]

I suggest you perform a diagnostic on your G. I plugged in my diagnosis computer tool and it gave me the following finding. Air quality sensor Has Malfunction.

 

[Rolf Redecker]

I suggest you perform a diagnostic on your G. I plugged in my diagnosis computer tool and it gave me the following finding. Air quality sensor Has Malfunction.

How easy is life without all those sensors