depends on the highway/road conditions. i'd think if you were only doing it for a short period of time, just to eliminate this as a possibility, no it would not hurt. assuming you dont have terrible road conditions or have something reasonably large go under the car.

 

Honestly, I haven't put back my plastic under tray since I last changed my oil. I drive highway often and haven't had any issues so far. The main thing to watch out for is dips and any items that can potentially go under your car like stripped tires, ply wood, rods, etc... I would say the most vulnerable part under there is the oil filter. Something smacking it at 40mph+ could definitely knock it off its seat and cause issues, leaks or oil spill.

Now, this only matters is if something goes under and through the underside. The undertray wont save anything from a lateral hit, like a speedbump. It only deflects horizontal objects.

The under tray has nothing to do with temperatures. If anything, it may have some affect on air flow efficiency/drag but its mostly for protection, deflecting rocks and such.

 

Dave, i live in Colorado as well and didn't use my undertray for a couple of years. It provides assistance with cooling and keeps the motor cleaner when driving in snow but you will be fine to drive with it off

 

Thanks for all the help!

Dave