Thinking of doing my first oil change on my 1990 300SE. I'm going with Mobil 1 15w50. I'm the previous owner of a 1985 300SD, so the filter situation is a bit different.

1. Remove oil filler cap and dipstick from engine
2. Place a pan to catch the appx 6.5 qts of oil under drain plug
3. Remove drain plug (looks to be about 14mm to me)
4. While draining (I usually let it go about an hour or so)
loosen oil filter (I have a 74 mm oil filter wrench) and
let draining continue.
5. After draining, remove old filter
6. Use a bit of fresh oil on rubber filter gasket and
install new filter
7. Replace drain plug with new washer fitted
8. Fill with 6 qts of fresh oil, check for leaks and proper oil level

SUGGESTIONS AND/OR COMMENTS WELCOME AS I DON'T WANT TO SCREW UP MY FIRST OIL CHANGE!

Pics of my "new" 300SE are here on the diesel forum:

http://www.peachparts.com/shopforum/diesel-discussion/316655-i-sold-my-diesel-buy-hope-i-did-right-thing.html#post2925836

Thats a good procedure you have there. Engine oil fill is more like 7qts, not 6. I think the official number is 6.8 When I fill with 7 it ends up just under max mark when I shut it off/check it later.

Use a good filter like a German made Bosch/Mann/Dealer Part filter not junk from the local store.

__________________
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'13 ML350 Bluetec - 95k - dad's (OC-98k)
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'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

There's no need to remove the oil filler cap or dipstick during the drain, but it won't hurt. The PCV system will allow air to enter the crankcase to replace the displaced oil.

To avoid a mess when you remove the filter, first loosen it a quarter turn - to make sure it will come off, then puncture the highest point. Now proceed to removing the pan plug. The filter will drain, and if you give it about 10 to 15 minutes, there will be little or no oil spilled when you remove it, but cover the bottom with a rag as you spin it off.

I also lift the car on the right rear jack pad to lower the oil drain, which allows a more thorough drain.

I have a "socket" that fits over the top of the filter than makes loosening it easy with a rachet and extension, but I don't recall the size. I think I took a new Bosch 72165 filter to a parts store years ago and found the correct oil filter socket that fit snugly.


The pan capacity is approximately 6.3 quarts, but I usually just install 6.

The oil pan bolt torque is 18 lb-ft, and I recall that the hex is 14 mm.

Used copper pan plug gaskets can be reused at least a couple of times by dressing them on a piece of mineral spirits wetted 220-400 paper on a flat surface - like a piece of glass - until the score marks are removed. I've never had one leak after this procedure.

You should use a CJ-4 (diesel) oil readily available at all auto parts stores. The conventional 15W-40 viscosity grade is okay for cold starts down to about 10-15F. If lower cold start temperatures are expected regularly use the "synthetic" 5W-40 CJ-4.

If you want to know why CJ-4, download the following pdf and read the article starting on page three.

http://stlouisncrs.org/news_files/St_Louis_NCRS_Chapter_July_2011.pdf

Vintage Corvette engine or M103 - they all have sliding surface valve trains and need the anti-wear additive level that is in CJ-4. Current S-category oils have less anti-wear additive to protect catalysts from contamination, but they have "roller everything" valve trains and don't need as much anti-wear additive as vintage sliding surface valve train engines.

Duke

If you use the correct oil filters there will be a check valve in the bottom and oil will not leak out when removed.

The OEM Mercedes filters use a special tool to enable them to be removed. Mann filters use the standardised tool.

I would just undo the oil filler cap and leave it sat loosely over the hole while the oil drains, just to be sure that nothing blows or drops in there.
I ran a 1992 300E (with cat) for ten years. It was switched to Mobil 1 0W40 at 89k ish miles by the MB dealer: the first 89k miles were on various brands of 10W40, all dealer filled.
The 300 estate (188bhp, non cat) has 189k ish miles on 10W40, but was switched by the MB dealer to Shell 5W40 a few services ago. Currently at 209k miles with the current fill of Mobil 1 0W40 (only because we had a can on the shelf).
The MB factory oil filters are made by Purflux (made en France afaik).

My MB dealer uses 5W30 in my 1988 300CE. When I have my indy change it, he uses the same. I' don't know what brand oil they use. It is not synthetic.
FWIW, my car has 132,400 miles on it and burns less than a qt. of oil between changes. Valve stem seals were replaced at approx 75k and significantly reduced oil consumption. Still running with the original CAT.
I live in southern New Jersey. Life is good.

edit: I gave up changing my oil a looong time ago.

Make sure the oil is hot. If you like you can use a suction pump and suck the old oil out of the oil dipstick tube.

On these cars, I like to use a suction pump through the dipstick. It's a breeze with the filter on top and not having to remove the plastic under shield or get under the car.