Problems for specific Mercedes-Benz 400SEL years:
Problem Reports
Problem with your car? See what our experts say or submit your own.
1993 Mercedes-Benz 400SEL Problems
Electrical Issues Due to Degraded Engine Wiring Harness
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.
Throttle Valves May Experience Electrical Failure
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.
Closing Assist/Door Lock Issues Due to Pneumatic System Problems
Problems with the pneumatic system can cause closing assist and door lock issues.
Squeaking/Worn Brake Pads May Require Rotor Replacement Also
Due to the size and materials of the brakes on these vehicles, the brakes start to squeak around the 50 percent wear point. The brake rotor surfaces become uneven, causing a lip to form at the outer edge of the rotor. Because of this, the rotors are usually replaced when the pads are worn (pad life varies depending on driving style and terrain).
Poor idle quality due to oil feed tubes falling into crankcase
Engine Oil and Coolant Leaks Resulting in Fulid Intermix
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 result in severe engine damage.
Emissions-related ports in cylinder head may clog
Excess Free Play in Steering and/or Alignment Issue
The tie rod ends, idler arm, and/or drag link components of the steering linkage may wear prematurely. Please keep in mind the wheel alignment should be checked and adjusted when any of these items are replaced.
High Usage Vehicles May Experience Ignition Lock and Tumbler Failures
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.
ABS Modulator Failure Due to Dirty Brake Fluid
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 help prevent this issue.
Power Window May Fail Due to Window Regulator
One or more door windows may stop working due to a failed window regulator. Replacement of the failed regulator will be necessary to correct this concern.
Cracked Driveshaft Flex Discs May Cause Driveshaft Movement/Vibration
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 driveshaft center support bearing, transmission, or differential can occur.
Head Light Lenses Become Cloudy/Opaque
The lenses for head lights may become opaque (cloudy or hazy) as a result of sun exposure. This can reduce the effectiveness of the lights. Our technicians tell us plastic polishes can improve the clarity of the lenses, but replacement of the lamp housings is necessary to regain full intensity of the lights.