Q: Ignition key not working - 1987 Mercedes-Benz 420SEL

The rearview mirror can be dimmed for increased visibility at night. When it is dark outside, the brightness of headlights in the rearview mirror can make it hard for you to see, so you should always dim your rearview mirror...

Your audio system is customizable so that it can sound best to your ears, and for your music. To adjust the sound, follow these steps: 1. Press the audio button until it displays the setting you wish to adjust. The...

Hi there. This can be caused by a number of things. If it occurred right after the work was done then you may want to have it double checked. They may have used poor quality wires or the wrong spark...

Hi, thanks for writing in. You most likely have spark plug wires (https://www.yourmechanic.com/article/how-to-check-spark-plug-wires-by-robert-tomashek) that are leaking spark and grounding out. You should try to replace the distributor cap and rotor (https://www.yourmechanic.com/services/distributor-rotor-and-cap-replacement), plug wires (https://www.yourmechanic.com/services/ignition-cable-spark-plug-wires-replacement) and spark plugs (https://www.yourmechanic.com/services/spark-plugs-replacement). This should...

Hey there. This is a common sign of a dirty or failing idle air control valve (https://www.yourmechanic.com/services/idle-control-valve-replacement). The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine. This...

Hi there. When the Advanced Trac light comes on and then the brakes are being applied, this means that the traction control system is active. The traction control is designed to apply the brakes to a wheel when the wheel...

Fuel is a possibility but so is air induction particularly the idle air control (IAC) valve (https://www.yourmechanic.com/services/idle-control-valve-replacement). The IAC valve may be sticking which would explain the first symptom you report which is everything was great until you simply put...

The brake system has rubber seals in it which are not compatible with mineral based oils of any kind. Introduction of these oils in to the master cylinder will cause the brake system seals to swell thus preventing normal operation...

Engine coolant can leak externally through a hose, radiator, water pump, etc. or internally due to a leaking head gasket and sometimes a leaking intake manifold gasket depending on the engine design. External leaks are typically found by simple pressure...