- 09/21/2020
- 5 Min Read
- By: Christian Schaefer
How To Change The Oil On a Mercedes C300 (M274 Engine)
Oil changes are an essential part of car ownership, and especially Mercedes-Benz ownership. The oil’s job is to keep everything inside the engine lubricated and happy. As the oil is used, its lubricating properties fade, leading to increased wear on the engine components. The new synthetic oils that companies like Mercedes use can last up to 7,500 miles, nearly triple that of conventional oil.
Changing your oil can be an important step in learning how to service your vehicle. Oil changes are some of the most basic jobs you can do at home and can make you more conscious of the importance of looking after your car.
Mercedes models and years applicable:
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Symptoms and effects of unchanged oil:
- Increased engine wear
- Decreased fuel mileage
- Decreased engine performance
In an engine, the oil’s job is to lubricate all of the moving parts. Without the lubrication, parts would wear rapidly, sending debris through the engine before it locks up.
Over time, the oil itself will degrade. The molecules inside of the oil break down, causing the oil to lose its viscosity. Modern synthetic oils last significantly longer than conventional oil, but still require scheduled changes. Always check with your vehicle’s manufacturer or its manual to find out how often your oil should be replaced.
What will it cost to complete a Mercedes M274 oil change?
The kit we sell for this job contains all of the parts needed and costs $64.29. For that, you get a new OE filter, all 7 liters of LIQUI MOLY oil, a new drain plug with its crush washer, and the oil filter housing seals.
It’ll cost around double that to have an oil change performed by an independent shop or dealership. On top of the extra charge, you’ll have to wait until they can get to your car.
How long will it take to complete a Mercedes M274 oil change?
The oil change process is not long. With the kit we provide and the proper tools at your disposal, the job shouldn’t take longer than thirty minutes.
Tools required to complete a Mercedes M274 oil change:
- Floor Jacks
- Jack Stands
- 8mm Socket
- 13mm Socket
- 27mm Socket
- Ratchet
- Torque Wrench
- Oil Extractor (optional)
Parts required to complete a Mercedes M274 oil change:
Steps required to complete a Mercedes M274 oil change:
Step 1: Change the oil filter
Open the hood and remove the engine cover. Grab it on either side and pull up to unclip it from the engine.
Next, remove the snorkel for the intake box. There is a retaining clip on the snorkel where it turns to run across the radiator support. Turn it to the left to release it. Then, unclip the snorkel tube from the radiator support and airbox. A few locking tabs hold on the snorkel tube. Push in and pull back on the ends of the tube to release the tabs.
The oil filter housing sits on the front of the engine under the charge pipe. Use a 27mm socket to loosen the oil filter housing cap. Finish backing out the cap by hand and then pull it out of the housing. Have a rag positioned under the housing as the oil will drip out of the cap during removal.
Pull the old filter off of the cap and then remove the three o-rings. A pick tool will make the o-ring removal quick and easy. Use a rag and some parts cleaner to clean off as much of the old oil as possible. Then, dab the new o-rings with some oil and install them onto the cap.
Slide the new filter onto the cap until it clicks. Then thread the cap back into the housing by hand to prevent any cross-threading. Use the 27mm socket to torque the cap to 25Nm.
Refit the air snorkel once the filter cap its torqued to spec.
Step 2a: Drain the oil (Without Oil Extractor)
Before leaving the engine bay, crack open the oil fill cap. Then, jack the car up and place it onto jack stands. Covering the bottom of the engine is a plastic splash shield held on with seven fasteners. Use an 8mm socket to remove the fasteners.
Don’t look up as you remove the splash shield; there will be dirt and debris trapped above it. Place a drain pan under the drain plug. Position it farther toward the driver’s side as the oil will shoot out in that direction. Use a 13mm socket to remove the plug.
When all of the oil is out of the engine, use the new copper crush washer and the drain plug supplied with the kit to seal the oil pan. Thread in the drain plug by hand to prevent cross-threading and, then use the 13mm socket to torque the plug to 30Nm. Reinstall the splash shield using the 8mm socket and then lower the car back onto the ground.
Step 2b: Drain the oil (With Oil Extractor)
Locate the oil level dipstick and remove it from the engine bay. Then, slide the fluid extractor’s hose down the oil level dipstick tube until it hits the bottom of the oil pan.
Set the valve on the extractor to pull rather than push, and then pump it a few times to start the extraction. The extractor should pull out six and a half liters of oil. If only five liters come out, adjust the hose in the dipstick tube.
Remove the hose from the dipstick tube and put the dipstick back into place.
Step 3: Refill the engine with oil
Open up the new bottle of LIQUI MOLY oil and pour in six and a quarter liters. The oil needs to make its way through the engine and down into the oil pan before you can check the level.
Wait around ten minutes and then check the level. If the oil doesn’t come up to the “full” line on the dipstick, add more in small increments until it does. Use a rag to clean any oil you may have spilled.
Once the proper oil level is reached, refit the engine cover and shut the hood.
Step 4: Reset the service indicator
Sit in the driver’s seat and put the key into position one. Once the cluster shows the mileage, hold down the “OK” and phone answer buttons until the menu that shows “Assyst Plus” appears.
Select “Assyst Plus” and then select “Full Service.” Scroll down and select “Confirm Full Service” when it appears. Select “yes” when it asks about the oil grade and then select “Confirm.”
Mercedes M274 Oil Change Torque Specs:
- Mercedes Oil Filter Housing Cap = 25Nm or 18.4 ft-lbs, of torque
- Mercedes Oil Pan Drain Plug = 30Nm or 22 ft-lbs, of torque
Just like that, your Mercedes-Benz is full of fresh oil and is equipped with a clean filter. If you’re interested in more DIYs for your Mercedes, you can visit mercedes.fcpeuro.com and subscribe to our YouTube channel.
