AC system leaks and/or a faulty evaporator temperature sensor can cause poor AC cooling. The failed sensor can prevent the AC compressor from coming on. Leaks cause a low refrigerant level, which reduces the ability to cool.
Problems for specific Mercedes-Benz ML350 years:
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Newest reported Mercedes-Benz ML350 problems
It is not uncommon for the power steering rack to develop a fluid leak requiring replacement of the rack assembly. Loss of power steering fluid may also cause an abnormal noise and damage to the power steering pump.
The engine may develop a stalling and/or no start condition due to a failed crankshaft position sensor.
The camshaft adjuster solenoid (which is related to the variable valve timing system) may fail or timing chain/balance shaft components may wear, resulting in illumination of the Check Engine Light and various drivability issues. Mercedes-Benz has released a service bulletin outlining specific repair instructions depending on fault codes stored.
The heater blower motor can become abnormally noisy. Replacement of the blower motor is commonly necessary to correct this concern.
The power steering return hose may leak at the radiator cooler fitting. If the clamp is not properly tightened, the hose can blow off, causing increased steering effort and a mess under the hood.
The door storage pocket can become unglued and fall into the door.
The power window switch may fail and the windows will not raise. The main switch at the front center console is commonly at fault. A failed switch will require replacement.
On vehicles with airmatic suspension, the airmatic pump relay can stick, causing a dead battery, because the pump continues to operate when it should be shut off. Eventually, the pump will fail; the pump, fuse, and relay will need replacement. After parking and exiting the vehicle, the airmatic pump should only run for a few seconds before turning off. It should not come back on until the driver's door is opened.
The insulation at the sunroof and on the inside of each door window glass can peel off. The loose insulation will then scrape the sunroof or window glass as it is operated. Replacement of the damaged insulation will be necessary to correct this concern.
After a heavy rain storm, the drains for the heating, ventilation and AC (HVAC) system intake can be plugged with leaves and other debris, causing a dead battery. Water fills the intake cavity and overflows into the vehicle, directly onto the blower motor and its regulator. This causes the regulator to short out and the blower motor will continue to run, despite the key being off and removed from the vehicle. Usually the carpet at the right front passenger floor will be wet too. If the carpet is saturated, the passenger seat may need to be removed to dry out the battery storage area before water or moisture reaches the relay and fuse holders. To prevent this, do not let leaves and twigs accumulate at base of windshield. If there are leaves or debris below the wiper blades, clean the area.
The covering for the center console can bubble and discolor. Replacement of the affected part is most commonly only way to repair this concern.
Motor mounts commonly fail, causing engine vibrations to be transferred to the body. Failed motor mounts should be replaced in order to prevent damage to the transmission mount.