Mercedes Diesel Oil Change
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All parts used in these pictorials are available at the diesel parts for sale page
Mercedes Diesel Oil Changing
I realized that I did not have some of the "basic" maintenance items for those new to the Mercedes diesels. I will start a whole series devoted to basic maintenance of these cars, just for those new to either car repair, or just new to the diesels. The car used in this pictorial is a 1985 300cd. The procedures for almost any Mercedes diesel will be almost the same.
Safety and security tips:
Please remember to recycle all your used fluids at an appropriate recycling center. Be mindful to not spill or splash fluids on yourself, others or the ground. Also as a safety tip please remember anytime you are working on, around or under your car, to wear safety glasses and secure the car with wheel stops and approved jack stands!
Basic layout of the 617 diesel engine.
Locate the oil filter canister on the drivers side of the engine and remove the 2 nuts holding the top on. Do this before you drain the oil from the pan. The reason is, when you remove the top and filter cartridge, the oil will drain back into the oil pan from inside the filter cartridge.
After removing the 2 nuts pull the canister cover straight up. Be careful NOT to disturb all the various vacuum connections you see next to the oil housing. Changing the oil is the number one reason for the car not turning off with the key. The reason is, most times a vacuum line will get disconnected and create vacuum leak. If you are new to these engines, just make a diagram of the lines so you will know where they go, if some get disconnected.
Pull the oil filter cartridge straight up and out of the housing. A couple of paper towels near by, will keep the mess to a minimum.
This is what the inside looks like with the filter removed. Notice that no oil remains after the filter and top are removed. The filter and top have O rings that seal against the bottom of the housing when they are inside, keeping the oil in the canister.
Now remove the drain plug in the oil pan.......
....and drain into a suitable container.
Please use a high quality oil filter! Mahle is an OEM supplier for Mercedes and is what I like to use. This particular brand also has a new drain plug washer and O ring. There are several other brands that I like also. The bottom part of the filter is the "full flow" portion. The top part is the "by-pass" element which diverts some of the oil into its chamber, to filter it to a smaller micro range.
The oil filter kit comes with a new O ring for the top. Do NOT reuse the old seal.
The 2 O rings on the end of the shaft seal into the oil housing. They are not included in the oil filter kit, but should be changed if they are no longer soft. I have them if you need them.
Place the new filter into the canister. Make sure to push it all the way in. The last 1/4 inch is a little snug so to get a good seal on the bottom. Do NOT pour oil into the canister to "pre-fill". It will just all drain into the oil pan.
Slide the top back on and install the 2 nuts. Just snug them down. You did remember to put the new O ring in the top right?
In the Mahle oil filter kit, you get 2 drain plug washers. I always use the copper one since copper will give an excellent seal when snugged against the oil pan.
Refill with your favorite oil. Start the car up and check for leaks. I told you this was an easy job.