1994 E420 oil change????
 

Hi,

Does the undercarriage cover need to be removed to drain the oil? My car has the wrong cover on because the screw wholes don't line up on mine. I just want to know so that I don't order the correct cover if I still have to remove it. Thank you.

To "drain" the oil yes, not to topside it. Those covers can be throw away with impunity.

I wonder why they just did not leave an opening for the drain plug. That would have been convenient.

There's a real possibility that one of the justifications for the belly pan was keeping you away from the drain plug and in the dealership for oil changes and other service.

they do appear to keep road debris/mud/snow off the bottom of the motor... and drips from the driveway if you have them... my mechanic said if i took it off the engine could "breathe" easier making it run cooler in the arizona heat

One purpose of the bellypan is to catch drips of oil from all the usual sources, including the oil pan. The dirty pan is proof that it works and the diaper layer was all rotted out so I removed it. The 124 diesel uses the thermo flap on the drivers side to regulate the air temp in the engine compartment, maybe this has to more usefulness in really cold weather?

I believe another function of the pan is to improve aerodynamics
I use a Topsider but once a year I take off the bellypan when changing antifreeze and at that time do an inspection. I've not had trouble w/ lining up screws in their holes but the wrong screw can spoil your morning. I finally bought some of the proper screws, they are an MB special part.

I throw them away first thing when I buy a car. My experience on 124/119 motors is that they run about 10 degrees cooler without the pan. They also mask fluid leaks of all kinds which is a bad thing on an older used car. If I have a fluid leak I won't know about it right away. And of course they make bottom side oil changes a bit harder. I think it's quite a bad idea to keep them on an older used car. They are by no means a necessity - 90+ percent of the cars on the road don't have them. But maintaining originality makes some people feel good.

me I use a pump suck it up from dip stick tube

Its not that hard to remove them (the covers) 4 or 6 - 8mm screws.

But yes..they are not necessary at all.