Mercedes-Benz S420 Repair and Maintenance

A guide to problems, costs, maintenance and repair for your Mercedes-Benz S420

Select your Mercedes-Benz S420's year to get more detailed information:
Repair Estimates

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Mercedes-Benz S420
$
112
to $
166
Mercedes-Benz S420
$
2,220
to $
3,372
Mercedes-Benz S420
$
353
to $
450
Mercedes-Benz S420
$
251
to $
371
Mercedes-Benz S420
$
742
to $
1,575

Mercedes-Benz S420 Problems

Closing Assist/Door Lock Issues Due to Pneumatic System Problems

Problems with the pneumatic system can cause closing assist and door lock issues.

Faulty Mass Air Flow Sensor Causing Erratic Engine Operation and Poor Fuel Economy

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 engine control module (ECM) takes the wrong information and delivers incorrect volumes of fuel to the cylinders.

Insulation Degrades on Engine Wiring Harness and Leaves Conductors Exposed

The engine wiring can degrade because the insulating material falls off leaving the bare wire exposed. This can cause many problems depending on which wires are exposed and what they touch.

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Mercedes-Benz S420 Recalls

Recall 96V058000
THE DRIVE BELT PULLEY ON THE ENGINE CAN DEVELOP FATIGUE CRACKS IN THE METAL AND BREAK. IF THE DRIVE PULLEY BREAKS, THE CAR WOULD NOT HAVE ENGINE COOLING, BATTERY CHARGING, AND/OR POWER STEERING.

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Mercedes-Benz S420 Reviews

the heater valve blowing warm air out of the vents and air condition works off and on. I was told if I by pass the heater valve Ill have good air condition but no heat until I replace the heater valve. rather have cold then heat right now. And I was told I can rebuild the heater valve, so 1, how do I bypass the heater valve and 2 is there a kit to rebuild the heater valve and where do I buy it?...
what cause my S420 Mercedes to lose power when accelerate from stop it sound like the plug missing fire it does it after driven a few miles stopping to a stop it get worse as I go along and stop at a red light or stop for any purpose.Sometimes when I shut car off and let engine cool down about30 to 45 minutes the car will run better.
heater dont work and shifter dont work it go in different spot drive is revers 3 is drive. what can i do.

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