My 240D has a plastic Oil filler cap. I dont like it. Both because I just dont like the look of a plastic cap instead of the older aluminum ones and because it leaks. I know I can get a newer version plastic cap for it but I'd prefer to use one of the older aluminum ones I pulled off a couple of junkyard cars. Question is would these older aluminium ones be too heavy for the neck of the oil filler hole given the vibration of the 240D? I dont want to wind up cracking the neck of the hole with a heavier cap banging against it. Was this a meaningful engineering move to switch to a plastic cap or was it just an economy measure?

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

As long as they use the same means of mounting they should interchange, that cap when locked in place should never be able to bang around, even the aluminum ones do leak some as the seal ages. My 82 has the plastic cap and my 80 has a metal one, the covers seemed the same to me....
My guess would be cost effectiveness, its a lot cheaper to inject plastic into a mold than machine and stamp a metal cap. Another reason may be for comfort, plastic tends to not wick/hold heat the same as aluminum, they may have had customer complaints of getting burned by grabbing hot caps.

__________________
Chris
64 190D R.I.P.
80 240D W/617 engine -for sale
82 240D -for sale

Economy. You should be able to replace the gasket too to stop the leak.

__________________
1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

You just need one of these:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1CQ0J3JZ420W0VVAPY&year=1981&make=MB&model=240-D-002&category=All&part=Oil+Filler+Cap+Gasket

I agree, the plastic caps look crappy.

I know this flies into the face of everything I usually stand for [ ], but for some reason I can't explain, I don't mind the plastic caps. I have plastic on the wagon, and metal of the 240. I don't have a preference, except the plastic one needs a new gasket......

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

My 240D has a plastic cap, it works fine but it just looks cheap to me. The metal one is a little warm on the fingers, but it looks like it belongs on that engine. I wouldn't lose much sleep over it, either way.