How to Maintain the Engine of a Mercedes Benz 420Sel

1. Change the oil and oil filter at least once every 10,000 miles. To do this, first jack up the front end of your Mercedes and set jack stands in place. Lower your Mercedes down on the jacks. Remove the oil plug with your socket set and let the oil drain into your drip pan. Replace the drain plug with your socket set. Remove the old oil filter with your oil filter wrench. Set it aside and then hand thread the new filter in place. Tighten it down with your oil filter wrench. Add 6 quarts of 10-W-40 oil to your Mercedes via the oil fill hole on the right side of the engine's manifold.
2. Check all your other fluid levels when you change the oil. These fluids include your transmission fluid, power steering fluid and brake fluid. To check the transmission fluid, start your Mercedes and then remove the transmission fluid dipstick located on the driver's side of the engine block towards the rear of the engine. Wipe the dipstick clean, stick it in and remove it. If you need transmission fluid, turn off your engine, stick a funnel into the filler hole and add the fluid. Replace your dipstick when your are done. The brake fluid reservoir is a round, plastic reservoir located near your transmission fluid dipstick. Remove the cap by twisting it off and read the indicator stick mounted on the inside of the cap. Add fluid if it's low. The power steering fluid reservoir is located on the passenger side of the engine block near the belt drive pulley. Remove the cap by twisting it off by hand. It also has an indicator stick mounted on the underside of the lid. If the fluid is low, add it.
3. Check your air filter when you change your oil. The air filter is mounted inside a small box on the top of your engine, towards the back on your 420 SEL. Remove the single screw holding the box in place. Once you've done this, pull the cover off and remove the filter. If it appears dirty, change it.
4. Tune up your Mercedes every 20,000 miles. To do this you should first mark the spark plug wires with a crayon or paper. Number the wires 1 through 8 in the order in which they are mounted on each side of your engine. Since your 420 SEL is a V-8 engine, there will be four plugs located on each side of the engine. Once you have marked the wires in numerical order unplug them by hand from the spark plugs. Use your spark plug wrench to remove the eight plugs. Insert the new ones, tighten them with your spark plug wrench and then attach the spark plug wires in the order you numbered them in before.