Close

Mercedes-Benz 400SEL Problems

Find the most common issues based on Mercedes-Benz 400SEL owner complaints.
Tap theto learn more about the most common Mercedes-Benz 400SEL problems.

Most Common Mercedes-Benz 400SEL Problems

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.
Problems with the pneumatic system can cause closing assist and door lock issues.
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.
Get a Repair Estimate
Guaranteed by certified locations nationwide. Learn more
RepairPal estimates are guaranteed at over 1,700 quality certified locations nationwide. Learn more
Looking for a particular Mercedes-Benz 400SEL problem?

2 Known Mercedes-Benz 400SEL Brakes Problems

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 oute...
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...

4 Known Mercedes-Benz 400SEL Drive Train Problems

High mileage vehicles may develop a transmission fluid leak from one or more of the oil seals.
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.
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...

2 Known Mercedes-Benz 400SEL Electrical & Lights Problems

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.
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.

5 Known Mercedes-Benz 400SEL Engine Problems

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...
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...
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 s...

1 Known Mercedes-Benz 400SEL Exhaust & Emissions Problem

Ports in the cylinder head related to the emissions air injection and EGR systems can clog; the cylinder head should be removed and the ports cleaned.

4 Known Mercedes-Benz 400SEL Heating & Air Conditioning Problems

The climate control system can fail or perform erratically due to internal problems with the climate control button electrical contacts. Replacement of the climate control assembly is commonly re...
A refrigerant leak may develop from one or more of the following AC components: AC compressor, hose manifold for the compressor, or the evaporator core. The loss of refrigerant can cause poor AC ...
Other than a defective motor, a bad switch or blower motor resistor assembly can cause an inoperative heater blower motor.

0 Known Mercedes-Benz 400SEL Maintenance Problems

7 Known Mercedes-Benz 400SEL Miscellaneous Problems

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

5 Known Mercedes-Benz 400SEL Suspension & Steering Problems

Some models have tandem hydraulic pumps—one section for power steering and the other for suspension adjustment. These pumps are prone to leakage from either section.
A worn steering dampening shock can cause a fluid leak at the front of the vehicle. If a leak is noted from the dampening shock, our technicians tell us that it should be replaced.
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 item...

30
Known Mercedes-Benz 400SEL Problems & Complaints

Instrument cluster lenses break easily.
Glove box hinges, the center console armrest, and the cup holders break.
A cracked or broken heater core outlet housing can cause a coolant leak near the bulkhead (firewall). Our technicians remind us that coolant leaks should be repaired in order to avoid overheating ...
Problems with the pneumatic system can cause closing assist and door lock issues.
Some models have tandem hydraulic pumps—one section for power steering and the other for suspension adjustment. These pumps are prone to leakage from either section.
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 s...
The head lamp wipers are easily damaged, especially by automatic car washes.
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...
The climate control system can fail or perform erratically due to internal problems with the climate control button electrical contacts. Replacement of the climate control assembly is commonly re...
Other than a defective motor, a bad switch or blower motor resistor assembly can cause an inoperative heater blower motor.
A refrigerant leak may develop from one or more of the following AC components: AC compressor, hose manifold for the compressor, or the evaporator core. The loss of refrigerant can cause poor AC ...
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.
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...
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...
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...
Get a Repair Estimate
Guaranteed by certified locations nationwide. Learn more
RepairPal estimates are guaranteed at over 1,700 quality certified locations nationwide. Learn more
Researching a Mercedes-Benz 400SEL?
Get maintenance costs, reviews, recalls and more.