Do It Yourself
Jerry Cole
 
Changing Your Own Oil
 
Possibly the most important maintenance task on your Mercedes-Benz is a regular oil and filter change.

Proper changes at the right interval have enormous impact on the longevity of your car’s engine: reducing wear of the piston rings, bearings, camshafts and crankshaft, and mitigating other problems. Oil and filters are cheap; engines are expensive.

Mercedes recommends that you change your oil and filter once every 10,000 miles or once a year in cars using synthetic oil. Personally, I change it once during the 10,000-mile service interval if it looks dirty, but always change it when the service is due. Even non-synthetic (“dino”) oils have come a long way from the old every-3,000-miles oil-change rule of thumb. I’ll usually change dino oil at about 5,000 miles or when it looks dirty. For cars that are rarely driven and don’t reach the mileage intervals, oil should be changed once a year, preferably at the end of the driving season.

Before diving in, make sure you have the right parts. Don’t skimp on quality. Purchase an original equipment oil filter from the dealer, from a reliable online source offering genuine Mercedes parts, or from an original-equipment manufacturer such as Mann. If your manual calls for a fleece filter, get it. There are paper versions of fleece filters, but your engine will know the difference sooner or later. Make sure your filter comes with proper gaskets and seals for the filter housing. If your filter doesn’t come with the copper seal for the oil drain plug (usually 12mm), often called a crush washer, get one. Reinstalling the drain plug with a used washer or none at all will lead to site leaks.

Use the oil that your owner’s manual recommends. If your Mercedes is from the mid-1990s or newer and says use Mobil 1 synthetic, use it. If your Mercedes is a diesel, make sure the oil is rated for diesel engines.

You’ll need a few tools: a jack and jack stands, wheel chocks, a 13mm socket or box-end wrench, an oil-filter housing socket (mid-1990s and newer cars), a nut driver, shop towels and a waste-oil pan. I prefer a wide, low pan that can be sealed and taken directly to an oil-recycling center. It should be wide so you don’t have to be the greatest shot when draining and low so the car doesn’t need to be jacked very far to clear it.

Just before starting the oil-change process, run the engine long enough to warm the oil. This will make the oil flow easier and hold the contaminants in suspension instead of sitting at the bottom of the oil pan. Set the parking brake, block the wheels and jack your Mercedes up just enough to clear the waste-oil pan and give you room to remove the protective cover panels (if present) to access the oil drain plug. Then place jack stands under frame or axles and lower the car until it is supported by the jack stands.

Using a nut driver and starting at the front, remove just enough of the cover panels to give you access to the oil drain plug. Position the oil drain pan underneath the drain plug and don’t forget to remove the plug or cap from the waste-oil pan  and open the vent, if present. Using a 13mm socket or box-end wrench, remove the oil drain plug. Make sure the copper-sealing washer came off with the drain plug and didn’t stick to the oil pan. Discard the old washer. Remove the oil filler cap from the engine to improve drainage flow.
 
After oil drainage has slowed to a trickle, remove the oil-filter housing cover. It may be attached with one 13mm bolt down the center or two 13mm nuts along the edge or made of black plastic that require a special socket (pictured) to remove. With shop towels at the ready, slowly remove the cover and filter. Let the filter drain into the waste-oil pan, then dispose of it properly.

Depending on the engine, there will be various rubber seals at the housing cover, and along a stem attached to the housing cover, if present. The old rubber seals can be lifted with a hook tool and then rolled off with your fingers. Wipe the old oil away, dab a small amount of new oil on the seals and reinstall them: Be careful not to twist them. Install the new filter and then the filter-housing cover. Don’t overtighten; about 15 pound-feet of torque should do it.

When the oil has stopped draining, replace the oil drain plug using a new copper-sealing washer. Tighten the drain plug to about 18 pound-feet of torque.

When refilling the crankcase with new oil, add the first five quarts while watching for leaks, then add a quart at a time, checking the dipstick frequently. Stop when the oil is between minimum and maximum on the dipstick and never exceed the amount called for in the manual.

Replace the oil filler cap and start the engine. Watch the oil pressure gauge to ensure the oil pressure rises after a few seconds. Once again, check for leaks. Shut the engine off and reinstall the protective cover panels. Lower the car down off the jack stands so that it’s level. Wipe the dipstick and check the oil again. If necessary, add just enough to bring the level to between the minimum and maximum marks.

After recording the mileage, it’s time to go for a drive and enjoy your Mercedes: You’ve earned it.
 


Based on model and year, you will need towels, new filter, waste-oil pan, oil-filter housing socket, 13 mm wrench and O-rings.
 


Close-up view of 240D and 300D oil filter cover.
 


E320/ML320 oil filter cover with torque data
 


E320/ML320 oil filler cap with overfill warning.
 


Single bolt closure S420 oil filter cover