What about the next owner of the car? Is he/she going to be surprised by a drain plug that cannot be removed? Fix it the right way by removing the rounded off plug with a pipe wrench and replace it.

I've worked in several GM dealers over the years and in some side shops as well and I've never seen anyone do it. I had always assumed it was a backyard method

Armchair logic says a free flow of oil from the drain plug will wash out any debris and "dirt" in the pan... and a tiny sucking tube won't... but we don't really have debris in there (if you do... you're way past worrying about an oil change). Seems to come down to convenience vs cost.

Not trying to argue but on a 617.952 if you look at the Tech Manual you put one liter more Oil into a new or rebuilt Engine then you do when you do a Oil Change.
That means there is one liter of dirty Oil left inside the Oil Cooler-Engine-Fuel Injection pump when you drain the Oil from the pan.

Since I already did the Oil Cooler Nipple Repair in My Oil Cooler I have been lossening the bottom Oil Cooler Hose end end and draining out as much as I can from there and a good dea of Oil comes out.

I don't take the time to drain the Oil out of the Fuel Injection Pump.

I am guessing the trapped dirty Oil in the system is a similar issue on other Engines but I am guessing access to the area you could drain it from is restricted and then there is always that chance of stripping the Oil Cooler Nipple threads.

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84 300D, 82 Volvo 244Gl Diesel

As I mentioned in a previous post there can be as much as a liter of dirty oil left in the in the Engine-Oil Cooler System-Fuel Injection Pump. A little bit left in the pan is not going to be an issue.

What is morre important is that the Oil Changes are done within a reasonable time of use and how you do it is not as important as doing it.

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84 300D, 82 Volvo 244Gl Diesel

As an old guy I remember a time when some engines used non detergent oil... like my 1949 IH340 tractor.... and I remember warnings not to change to the new detergent oils because it would clean and put into suspension a lot of built up gunk.

For those who did want to change... there were proper warnings to change out the oil filter quickly and often until there was evidence that no further avalanche of crud was being loosened...

But for engines which have always had detergent oil in them.... and had normal oil and filter changes during their lives... I suspect there is little ' dirt' in the system which could cause problems...or the ' dirt' is in a place it will stay unless harassed... like the bottom of the pan..... . I suspect more important is the lubrication properties of the oil which may be deteriorated due to oxidation and contamination.

I like the warm feeling and the visual I get from changing the oil via the oil plug and that ' dirt ' in the bottom of the pan being exited from the engine completely...

BUT I suspect that is a psychological bias not supported by any physics of the situation... and that our engines which have a dip stick tube sucking design ability....and a huge oil filter.... are perfectly served by regular changes of the proper oil and filter...

And being old enough to remember Non detergent oil... I am also getting to where the ability to change the oil and filter while standing up.... is increasingly important to me..
So I am thankful to those Germans who seem to have planned ahead... and appear to have approved of pulling the oil from the dip stick tube.

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Hey Leathermang!

At my advanced years a hoist is necessary. I simply can't crawl around under them any more and I wouldn't do what I do if that was a requirement. I've had a hoist for about 20 years +/- and I heartily recommend it. My current one is from Pace Tools (found them online) and was $1700 delivered to my driveway. The last time I looked the price was about the same - IIRC $1300 + delivery. The structure is from China and seems plenty stout and the pump is a standard American brand (the name escapes me right now). The hard part is having enough overhead space but most of us can find a way to work that out. In Texas I'd wager that it could even be outdoors and do OK for much of the year.

I expected to be swamped with requests to use it but actually that has rarely happened - a couple of buddies in MI and mostly our great neighbor here in NC a couple of times. If I had a buddy with a hoist I'd be bugging him/her all the time!

So changing oil does NOT involve crawling under a car for me. Something to consider.

Dan

Do you happen to know that spec?