1991 Mercedes-Benz 420SEL Oil Change Cost

To change the oil, a technician allows the engine to cool down, then removes the drain plug at the bottom of the engine oil pan and drains the oil. As the oil is draining they will remove and replace the oil filter. When the oil has fully drained the drain plug is re-installed and the engine is filled with the proper type and amount of new oil. The engine is started and checked for leaks. Finally, the engine is switched off, the oil level rechecked, and the maintenance light reset. While the oil is being serviced, the technician will note any obvious issues with the condition of the engine seals, amount of oil drained, last service date and mileage, and the drained oil's condition. If any abnormalities are noticed, recommendations for diagnosis or repair are made. Most manufacturers have now included panels that are attached to the vehicle's underside; they offer a measure of protection from debris and a means of controlling air flow to the engine and around the vehicle. These panels often completely cover the engine/transmission from below, blocking all access. Removal of one (or more) of these panels and their correct re-installation adds two new steps to the process of an oil change.

When changing or adding engine oil, follow the manufacturer's recommendation for the grade, often referred to as "weight" (0/30W, 5/30W, 20/50W, etc.), and type (petroleum or synthetic base) of oil to use. The grade is based on the oil's ability to flow - "viscosity". Modern engines are especially sensitive to the kind of lubricants used. Using an incorrect type or grade can cause the oil pressure light to illuminate, the engine to make abnormal noises, the check engine light to come on and may invalidate your manufacturer's warranty. So, always ask what oil you are getting, and know what is recommended for your car. Consulting your owner's manual is the best way to ensure you are using the correct fluids for your vehicle.

An engine oil change can be performed by intermediate DIYers. However, before attempting this service or ordering parts, be sure to look up the specifications and procedures for your particular vehicle. Most will require raising the vehicle to access the oil pan drain plug, and it is critical that the oil is refilled to the proper level, and that the oil filter is installed correctly. If there is any concern about completing this service properly, consider contacting your local RepairPal Certified shop.