Problem Reports
Problem with your car? See what our experts say or submit your own.
1991 Mercedes-Benz 300SEL Problems
"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.
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.
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.
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.
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.
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.
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.
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
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.