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Mercedes-Benz E420 Problems

Find the most common issues based on Mercedes-Benz E420 owner complaints.
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Most Common Mercedes-Benz E420 Problems

Due to wear, high usage vehicles can experience ignition lock and tumbler failures. The ignition lock cylinder will generally require replacement to correct this concern.
Oil feed tubes break and fall into the crankcase (engine) and the tappet becomes noisy (ticking), resulting in degraded idle quality. Our technicians recommend replacing all of the tubes at the sam...
A coolant leak may develop form the Radiator due to degradation of its plastic components. Replacement of the failed radiator will be necessary.
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2 Known Mercedes-Benz E420 Brakes Problems

As brake fluid becomes dirty over time, it can cause a failure of the anti-lock brake system (ABS) modulator assembly. Our technicians recommend a complete brake system flush every two years to hel...
The brakes may begin to squeak at about the 50 percent wear point. This is due to the size and material used for the brake pads and rotors. The brake rotor surfaces become uneven, causing a lip t...

4 Known Mercedes-Benz E420 Drive Train Problems

High mileage vehicles may develop a leak from one or more of the transmission oil seals.
A vibration felt through the center floor of the vehicle can be caused by cracked and/or shredded driveshaft flex discs, resulting in excessive driveshaft movement. If not repaired, damage to the...
The bushings for the shifter lever wear out to the point where they break and fall out. This causes excessive movement (loose feel) in the shifter lever and a clanging-type noise when changing gears.

7 Known Mercedes-Benz E420 Electrical & Lights Problems

The electronic throttle assembly may suffer an electrical failure. It is often cheaper to send the valve to a service center for repair that to purchase a new part.
Instrument cluster displays tend to fail, especially the clock and gear indicators; the instrument cluster needs to be replaced.
The third (high) brake light housings melt, resulting in a loss of electrical contact for the light, which stops working. A complete housing (contacts and lens) is needed to repair the problem. ...

5 Known Mercedes-Benz E420 Engine Problems

Oil feed tubes break and fall into the crankcase (engine) and the tappet becomes noisy (ticking), resulting in degraded idle quality. Our technicians recommend replacing all of the tubes at the sam...
A coolant leak may develop form the Radiator due to degradation of its plastic components. Replacement of the failed radiator will be necessary.
The cooling system hoses may fail unexpectedly. The hoses can look good on the outside, but the rubber can degrade and erode on the inside. If not carefully checked, the hoses can burst at any ...

5 Known Mercedes-Benz E420 Exhaust & Emissions Problems

Failed spark plug wires and/or ignition coils can cause intermittent misfires (rough running); the Check Engine Light may also illuminate. Diagnoses of the ignition system will be necessary to dete...
The mass air flow sensor can fail, resulting in poor fuel economy and Check Engine Light illumination.
When the engine is running, but the vehicle is not moving, a rattle heard from beneath the vehicle could indicate that one of the exhaust catalytic converters has failed. The substrate (the intern...

4 Known Mercedes-Benz E420 Heating & Air Conditioning Problems

A malfunctioning HVAC blower motor regulator can cause the blower motor to operate below the requested speed or not at all. Updated regulators are available; the blower motor and cover need to be r...
One or more blend door vacuum actuators may fail resulting in the incorrect output temperature from the HVAC system. Failed actuators will require replacement to restore proper HVAC operation.
Due to wear of mechanical parts in the control head, the buttons on temperature control assemblies work erratically or not at all. These control heads need to be replaced for this concern or when t...

0 Known Mercedes-Benz E420 Maintenance Problems

8 Known Mercedes-Benz E420 Miscellaneous Problems

Due to wear, high usage vehicles can experience ignition lock and tumbler failures. The ignition lock cylinder will generally require replacement to correct this concern.
The sunroof may not work correctly due to failed components as a result of age and wear. Repairing a sunroof can be labor intensive and very costly.
Due to age and sun exposure, the interior wood trim cracks and the finish gets a cloudy haze. Replacement if the trim would be the most common solution to the problem.

6 Known Mercedes-Benz E420 Suspension & Steering Problems

The lower control arm bushings can wear and crack, resulting excessive movement at the control arm pivot point, leading to irregular and premature tire wear. Worn Ball joints can also cause similar...
A squeak from the steering column is often related to a rubber boot in the column or a seal in the power steering rack.
A fluid leak from the front of the vehicle may be a result of a worn steering dampening shock. Our technicians tell us that if a leak is noted from the dampening shock it should be replaced.

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Known Mercedes-Benz E420 Problems & Complaints

The seat springs and padding break down over time, causing a lean, tilt, or sag.
The sunroof may not work correctly due to failed components as a result of age and wear. Repairing a sunroof can be labor intensive and very costly.
Due to age and sun exposure, the interior wood trim cracks and the finish gets a cloudy haze. Replacement if the trim would be the most common solution to the problem.
A knocking noise from the front end can be caused by cracked strut tower bushings.
Oil feed tubes break and fall into the crankcase (engine) and the tappet becomes noisy (ticking), resulting in degraded idle quality. Our technicians recommend replacing all of the tubes at the sam...
The emissions air injection pump can seize, causing a loud squealing noise followed by smoke from the drive belt. If the engine is not turned off, the belt will break, turning on the alternator/bat...
One or more blend door vacuum actuators may fail resulting in the incorrect output temperature from the HVAC system. Failed actuators will require replacement to restore proper HVAC operation.
Due to wear of mechanical parts in the control head, the buttons on temperature control assemblies work erratically or not at all. These control heads need to be replaced for this concern or when t...
A faulty mass air flow (MAF) sensor can cause erratic/rough engine operation and fuel economy issues. Since this sensor measures the actual amount of air entering the motor, when it fails, the engi...
Failed spark plug wires and/or ignition coils can cause intermittent misfires (rough running); the Check Engine Light may also illuminate. Diagnoses of the ignition system will be necessary to dete...
Cup holders break easily, especially if sticky liquids are spilled into the cup holder mechanism.
Vehicles with automatic level control that ride harshly in the rear (no give in the suspension) may have one or both dampening actuators which have failed. It is commonly recommended the actuat...
Due to exposure to the sun, lenses for head lights may become opaque (cloudy or hazy). This reduces the effectiveness of the lights. Our technicians tell us plastic polishes can improve the clari...
The evaporator temperature sensor can fail, causing the AC compressor not to cycle. If the AC compressor does not turn on, the AC system will not blow cold air. If the compressor is stuck on, the a...
Internal and External engine oil & coolant leaks can develop from the head gasket and/or timing cover gasket; these leaks should be repaired before the engine oil and coolant intermix which can...
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