Plastic cover below engine. What's it do?
 

2013 G37 6MT, 6000 miles. I changed the oil for the first time today. After a few minutes looking around for a drain plug, I finally decided to RTFM, and learned that I had to remove this giant plastic cover that was hiding the bottom of the engine. Once I got that off, access was easy.


So now I'm wondering: why is that cover there?


Does it improve aerodynamics to give better fuel economy?


Decrease lift so I get better handling at triple-digit speeds? :-P


Keep the engine bay clear of road grime?


Enquiring minds want to know...

Im guessing the cover protects from road debris getting into the belts/pulleys or any moving components i.e alternator, AC. Also, I wouldn't like any rocks hitting the oil pan either.....it might also help reduce the drag of the car :dunno:

It's a splash shield. It is creased so that you can access the oil drain bolt and filter simply by removing the 4 rearmost bolts and folding it down. No need to completely remove the whole thing completely.

Splash shield. It's good for areas that get alot of moisture as it keeps the cold water from coming in direct contact with exhaust manifolds, main seals, belts and such. When many of these items are at operating temp, they don't like being cooled off in an instant via a massive dose of mud puddle. When I was younger, cars didn't have these shields and the cold water would often cause my headers to bend and tweak just slightly, causing the gaskets to shift and leak and need a retorque. I'm sure they help with aerodynamics as well. Cheap protection.

PITA to fold down and keep it folded down and out of the way. I use a c-clamp locking wrench to keep it folded.

I use Penzoil Ultra which comes in a 5 qt. jug. With my car on the ramps I use for oil changes, the full jug of oil is the perfect height to hold the shield down out of the way. Just fold it down and put the oil jug in place on the ground to block it from folding back up. Works for me.

The splash shield really does function in more ways than you might think. It does smooth airflow under the car to reduce drag. It guides high pressure air through the radiator and out through the engine bay. Since it bolts up to the lower valance of the bumper, it also serves to stiffen the entire structure and resist deformation and damage.

I just use an extended bottle jack to hold the plastic back out of the way, holds the back portion just fine.

Used to use a 5 qt jug just like Jeremy but it was a PITA. Maybe because I use a low profile ramp. I replaced the shroud and now oil change is a breeze.
Highly recommended if you' re planning to keep your car long and if you do oil changes frequently.
08-Up G35 G37 Z Speed Performance Aluminum Engine Under Shroud