Problem Reports
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1990 Mercedes-Benz 500SL
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.
Hard/soft Tops May Develop Problems Due to Age
As vehicles age, various problems may develop with the hard and soft tops. If problems are encountered, it would be recommended to have a technician familiar with these tops perform the diagnoses.
Erratic Engine Operation and Poor Fuel Economy Due to Faulty Mass Air Flow Sensor
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.
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.
Automatic car washes can damage head lamp wipers
The head lamp wipers are easily damaged, especially by automatic car washes.
Poor idle quality due to oil feed tubes falling into crankcase
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 same time, broken or not.
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.
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.
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.
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.
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.
Emissions-related ports in cylinder head may clog
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.
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.
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.
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.
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.
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.
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.
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.
Cracked strut tower bushings may cause knocking noise on front end
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.
Harsh Ride From Rear Due to Failed Dampening Actuator
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 actuators be replaced in pairs.
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).
Poor AC Performance Due to Refrigerant Loss
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 performance. Our technicians tell us that proper leak diagnoses should be performed in order to determine the cause of any refrigerant loss.