Did a search and found nothing.

My undershield cover got torn up and so I removed it. Any reason I should replace it.....it's a PITA on oil and transmission fluid changes!!

 

Haven't put mine back on in some time. More annoying than anything

 

There is no reason why you HAVE to put it back on there...

 

It might reduce the noise level a bit. Some engine covers are engineered to do so.

 

I thought it was to protect the engine bay from unnecessary water intrusion via splashing that would lead to corrosion.

 

I always thought it was for aerodynamics and to prevent various potential shrapnel from hitting the bottom of the engine.

 

Technically, yes, but its not ABSOLUTELY necessary... I personally wouldn't take it off my car, but that's me. What puzzles me is the fact that it gets in the way of oil changes for OP. I can reach the filter by turning the steering wheel all the way to the right and the drain bolt is exposed....

 

You know? You're right....I can change the oil with it on. I was thinking of my Volvo.
The service guy cited protection from rocks as the reason it's there.

 

The transmission plug is definitely blocked, but I would think you could southern engineer a solution to that without removing the whole thing.

The small rock idea makes sense. My Tundra has a 1/4" steel plate for big rocks.

 

I recently replaced mine as someone hacked the hell out of the old one not sure for what purpose but it was virtually non existent. I was quite pleased on the replacement cost vs my M5.

I keep these on all my cars but is it "necessary", no! I do think in my instance it lends some structure to front bumper to tie it down a bit esp with underbody spoiler I have.

 

Apologies for dumb answer. Somehow I didn't read the word "undershield." Duh.