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1990 Mercedes-Benz 300SL Problems

Find the most common issues based on 1990 Mercedes-Benz 300SL owner complaints.
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Most Common 1990 Mercedes-Benz 300SL Problems

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.
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...
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.
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2 Known 1990 Mercedes-Benz 300SL Brakes Problems

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 t...
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 1990 Mercedes-Benz 300SL Drive Train Problems

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

2 Known 1990 Mercedes-Benz 300SL 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.

6 Known 1990 Mercedes-Benz 300SL 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...
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.
A coolant leak may develop form the Radiator due to degradation of its plastic components. Replacement of the failed radiator will be necessary.

3 Known 1990 Mercedes-Benz 300SL Exhaust & Emissions 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.
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...
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/bat...

3 Known 1990 Mercedes-Benz 300SL Heating & Air Conditioning Problems

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 ...
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...

0 Known 1990 Mercedes-Benz 300SL Maintenance Problems

4 Known 1990 Mercedes-Benz 300SL Miscellaneous Problems

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.
On high usage vehicles, the ignition lock may become difficult to turn due to wear of the ignition lock and tumblers. Replacement of the ignition lock cylinder will generally be required to correct...
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 ...

5 Known 1990 Mercedes-Benz 300SL Suspension & Steering Problems

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 i...
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 ...
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.

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Known 1990 Mercedes-Benz 300SL Problems & Complaints

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.
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...
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.
A knocking noise from the front end can be caused by cracked strut tower bushings.
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.
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/bat...
The head lamp wipers are easily damaged, especially by automatic car washes.
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 ...
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 ...
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...
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 ...
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.
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