Problem Reports
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1991 Mercedes-Benz 300SE
Transmission Oil Seals May Leak on High Mileage Vehicles
High mileage vehicles may develop a transmission fluid leak from one or more of the oil seals.
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.
Squeaking/Worn Brake Pads May Require Rotor Replacement Also
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 to form at the outer edge. This will generally require replacement of the rotors when the pads are worn (pad life varies depending on driving style and terrain).
Noise and/or Smoke From Drive Belt Area
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/battery warning light.
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.
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.
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.
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.
Coolant Leak/Overheating Due to Radiator Leak
A coolant leak may develop form the Radiator due to degradation of its plastic components. Replacement of the failed radiator will be necessary.
Bad Switch/Blower Motor Resistor Assembly May Cause Inoperative Heater Blower Motor
Other than a defective motor, a bad switch or blower motor resistor assembly can cause an inoperative heater blower motor.
Coolant Hoses May Fail Unexpectedly
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 time.
Climate Control System Problems Due to Wear in Climate Control Buttons Contacts
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 required to correct this problem.
Check Belt Tensioner When Replacing Water Pump
A coolant leak may develop from the water pump. When replacing the water pump, the drive belt tensioner should be inspected and most likely replaced as well.
Fluid Leak From Front of Vehicle
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.
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.
The Differential May Develop Leaks From the Seals or Cover
Leaks may develop from the differential seals and/or cover on older or high mileage vehicles. Our technicians recommend a complete reseal of the differential unit when these leaks are addressed.
Shifter Lever Bushings May Break Causing Loose Feel/Noise
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.
Rough Running Engine Due to Misfire
A rough running motor or lack of power can be caused by a failed distributor cap or rotor, ignition wires (or their resistors), or valve cover gasket leaks. If the valve cover gasket leaks, oil can pool where the ignition wire resistor connects to the spark plug. The resistor can fail and the spark plug may not fire because of a short circuit through the oil.
Failure of EHA valve may cause fuel/engine problems
Fuel leaks, erratic or rough engine operation, and fuel economy issues can be caused by the failure of a fuel system component called the EHA (electro-hydraulic actuator) valve.
Part that attaches distributor rotor to camshaft may break
Instrument Cluster, Turn Signal/Wiper Combination Switch May Fail
The instrument cluster, along with the turn signal and wiper combination switch, can fail.
Motor Mounts Fail and Cause Vibration in Body
Motor mounts commonly fail, causing engine vibrations to be transferred to the body. Failed motor mounts should be replaced in order to prevent damage to the transmission mount.
Premature Tire Wear Due to Cracked Lower Control Arm Bushings
The lower control arm bushings can wear and crack, leading to irregular and premature tire wear. Worn Ball joints can also cause similar tire wear problems. I some cases it may be necessary to replace the lower control arm, including bushings & ball joint to correct this concern.
Expansion valve may get stuck
Worn seat springs/padding may cause lean or sag
AC Not Cold Due to Leaking Hose
A refrigerant leak may develop from one or more of the AC hoses. Proper leak detection procedures should be followed if refrigerant loss in encountered. Replacement of any leaking hoses will we required to restore proper AC operation.
Early-style stainless steel fuel injectors may develop fuel leaks
Early-style stainless steel fuel injectors may develop fuel leaks. On high mileage vehicles, the fuel distributor may leak.
Improper Temperature Output From HVAC
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.
Fuel system components may leak and cause hard starting problems
Interior Wood Trim Cracks Due to Age and Sun Exposure
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.
"No start" Caused by Failed Fuel Pump/Relay
The fuel pump and/or fuel pump relay can fail, causing the car to crank over but not start. Proper diagnoses will be necessary to confirm if the pump or relay is at fault.