The Symptoms of a Faulty W221 Airmatic Valve Block

The Symptoms of a Faulty W221 Airmatic Valve Block

The w221 airmatic valve block distributes the pressurized air produced by the air compressor to each of the four corners of your car that use air suspension. These air connections are commanded by the ECU, and the valve block ensures that the correct amount of air is sent to each individual corner based on their specific ride height requirement.

A faulty valve block can cause the car to sag in one or more corners, as well as cause the air compressor to overwork itself and overheat leading to premature failure. The air supply to the compressor from the valve block is usually depressurized when not in use, this helps reduce heat build-up on the compressor. The valve block also contains six solenoid valves that must be working properly to provide the proper amount of air to each individual air strut or air spring.

One of the most common reasons for a faulty valve block is the O-rings can dry out, causing air leaks and overworking the electrical solenoids within the valve block. This can result in damage to the air compressor through excessive overworking and air leaks, and moisture damage to the electrical components of the valve block itself. Arnott provides direct-replacement solenoids with new O-rings to help you avoid these expensive repairs.

Another reason for a faulty valve block is that the valve block can overheat and become sticky, which can cause the solenoid to fail. Generally, the symptom of overheating will show itself by an air strut that doesn’t rise with the air compressor activated. A faulty valve block can also cause the air strut to become stuck at its lowest position, again preventing it from raising with the air compressor activated.

Lastly, the air pressure in the valve block can decrease due to a failed dryer, which is responsible for keeping water and other debris out of the air system. Normally the air dryer is blown out during a service, but it can become clogged with debris over time.

The w221 airmatic valve block can be very easy to diagnose and replace, but it is important to understand the symptoms of a faulty valve block before starting work on your Mercedes-Benz. Many of the same symptoms are the same as an air spring or air compressor problem, so it is important to rule out those issues before you spend money on unnecessary repair.

If you are ready to start troubleshooting a faulty w221 airmatic valve block, it is best to have a few tools with you. The most useful tool will be a diagnostic air suspension voltmeter, which can verify whether or not you have sufficient pneumatic output to raise the vehicle, as well as test each of the individual solenoids in the valve block for function. You can also use a leak detector to find any small air leaks. It’s important to apply the leak detector at the appropriate locations, as some of these are very small and may not be immediately apparent.

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