Hello Peter,
These engines have two piece oil pans. The upper aluminnum pan and the lower steel pan.
The W113 cars actually had three versions lower steel oil pans and at least three versions of the upper aluminum oil pans.
The first version (lower) used on the 230SLs, 250SLs and various MB sedans, had an 18 bolt, smooth bottom, steel oil pan. It used a pan gasket #189 014 0022.
The second version (lower) used on the 280SL and various Mb sedans, had a 19 bolt, smooth bottom, steel oil pan. It used pan gasket #108 014 0080.
Both these early types used the "larger" drain plug (17mm hex, replaced by the 14mm allen style).
The third version (lower) #110 010 0313 was actually supplied in Febuary 1972 (after the end of W113 production). These are the correct replacements for the 280SL series and all M130 engines. They have some improved features and are considered an upgrade. This last version is a 19 bolt, "ribbed bottom" steel oil pan with a smaller 13mm hex drain plug. This version is deeper and increases oil capacity 0.5 liters. The ribs add strength and slight cooling capacity to the steel pan. The smaller drain plug has less of a tendancy to be knocked loose from road hazards.
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The factory supplies a rubber adapter for oil pick-up for the oil pump to be used with the new "ribbed" pan. It extends the oil pump pick-up furhter into the new deep pan. This adapter along with the oil pump strainer #130 180 0655 should be replaced before installing the ribbed pan.
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In addition, the latest version upper aluminum oil pan supplied by the factory is also an improved design. This aluminum upper oil pan produced after W113 production, has cast aluminum fins or channels cast inside the oil pan to help direct oil back into the lower pan. I suspect these ribs also improve engine oil cooling capacity also.
These improved parts are most likely what you would recieve to replace your originals from Mercedes? In addition these seem to be the standard parts used on the later M110 Mercedes six cylinder engines so there is a good supply of good used units out there.
Some facts; You cannot replace your 18 bolt steel oil pan with either 19 bolt oil pan unless you replace the upper aluminum oil pan also. You can replace your smooth 19 bolt oil pan with a steel ribbed version as long as you add the oil pump adapter. You can convert your earlier engine by changing the upper aluminum oil pan after which you can use the latter improved ribbed steel pan. be aware that the dip stick arrangement in these pans vary slightly also so you would need the correct dip stick also.
The latest versions of Factory Shop Manual cover some of this information Sec. 18-6/1
I will post photos in the next couple of days.
Joe Alexander
Blacklick, Ohio
