Hey Guys, I'm updating my 1999 diesel 2500. The lower air dam which came on this truck has long disappeared. Does anyone know why these were fitted. Looking at my original window sticker it was optional at a cost of $25.

Also, does anyone know what was used to attach the air dam to the bumper? I don't see anything plastic under there.

 

Aerodynamics. Fuel savings.

 

Yep, on paper people in white lab coats with clip boards could prove theoretically, under certain circumstances, in perfect conditions on days ending in the letter "Z" it could improve mileage by a certain (tiny) amount.

In practice under the majority of real world conditions you're unlikely to see any benefit.

I know I once bought an '05 GMC Canyon new (great little truck BTW). I remember one guy on an owner's forum claiming he lost 2mpg by removing the front bumper valance, which I considered unbelievable. I was also getting ready to remove mine because I find such things bothersome and intrusive, and inevitably they get damaged and then look like a**.

So, I yanked mine from my Canyon.....back then I was religious about recording every fill-up and distance traveled per tank in a notebook in the glove box. My numbers found absolutely NO change in mileage with or without the valance.

And, as always, YMMV -- literally!!!!

 

On these truck not really much to em, be careful on newer trucks though it seems to be coming more important depending on what engine cooling package ect the truck is equipped with across all makes and models

 

Aerodynamics and aesthetics. Bumper looks much better with than without. Attach with bolts and plastic push pins.

 

I would think more looks, A truck with a foot+ of clearance underneath i cant see how a spoiler is going to make any difference. But then again it can direct air witch way to go and not cause drag.

 

It certainly looks nice mounted under the bumper. My truck didn't have one when I bought it, so I found a used one and added it, along with the factory tow hooks.

 

My '96 has it but I've seen similar trucks without it. It's just bolted to the bottom of the bumper. I think the trucks have a more balanced look with it but as for function, it smooths air flow under the vehicle. On a car, it will make a noticeable difference. On my CX-5, the dealer left it off once and it made a big difference in mileage. On these trucks, it might make a slight difference. Then again, maybe not. Instead of being like a ballet dancer like a car, our trucks are more like clog dancers. (In the apartment over your bedroom.)

I'm cheap enough I want to save money on fuel. I'm realistic enough to know my truck will never be great on fuel. Look at a truck like yours with the air dam. If you like it, get one and put it on.