Replacing lost wheel well arches
 

I know this isn't exactly a super hypermiling mod but I could use some help.

At some point over the last couple of weeks my front passenger side wheel well arch fell off the car. This is the thing that blocks rain, mud and wind from whipping around in there. I don't know how it happened or when.

I am getting a very prominent wind/whistling/whooshing sound from that wheel well. I'd like to fill in the area but I don't want to fork over the $100 or so to replace it.

Can I use that cloroplast stuff that everyone always raves about? Would it hold up as a temporary replacement while I wait on some cash for the new one?
Does anyone have any experience with this?

It produces enough wind drag that the car pulls to the right while driving at speed and I know that my wheels are balanced and aligned.

have you tried finding one at a junkyard?

ummmm....no. I don't know why that hasn't occurred to me.
Durh.

Any material suggestions for making an inner fender that is durable?

While the OP has other options, I'm still interested in an answer since I would have to make my own. My truck has big, gaping rear wheelwells and there was never an inner fender that fit in there, so I can't go to the junkyard to get one. I thought about making a coroplast panel to fit in there but I'm concerned about rocks and debris hitting it and destroying the panel.

I would think that as long as it's secured, coroplast would work fine. I can't imagine a rock really tearing it apart, at least not one the size of what would be flying through the wheel well. It'll get dirty, and maybe scratched up, but it's a wheel well, that's what it's there for.

How about getting a pair of plastic or steel mud guards/fenders from a trailer suppliers, like this:
http://www.cmf-engineering.com/images/cm2655.jpg
Or this:
http://www.made-in-china.com/image/2...-and-Truck.jpg
Find one that would be a good fit to the wheel size and wheel well and then bolt or rivet it inside the truck wheel well.

Other Truck Models Inner Fender
 

You might also look at other make/models for one you can use or adapt. I know I have seen some late model dodge's with inner fender liners in the rear wheelwells...
I think it was a 1500 with the Rumblebee package. Might also be on the regular 1500's but I am not sure.

metal wheel wells are going to be loud from rocks and water. My focus came with syrofoam in the wheel wells, and it is nice and quiet.

Take a new plastic trash can, cut the bottom out, one cut down the side and cut to fit your wheel well. Secure with self tapping or existing screws.