Does a car wash increase mileage?
 

Does a car wash increase fuel mileage? If so, how much? Does anyone have data - or data sources - on this?

On a similar note - I've heard something about a layer of film to apply to your car after a wash to protect from minor dirt, water, etc. to reduce the needs for car washes in the future. Different from a full wax, but somewhere in between. Thoughts?

Can't see a car wash making much difference. I guess you are thinking it might be more aerodynamic after a wash or even a bit lighter but I reckon the differences would be so tiny as to be incapable of measurement.

I remember seeing a study a couple years ago that showed that freshly waxed cars had slightly less aerodynamic drag, so in a way a clean car is more efficient.

Might save you a dollar in fuel, but it would cost more than that to wash it every month.

A car that is kept clean generally lasts longer and has a higher resale value as well.

https://www.youtube.com/watch?v=NNKMOqpfM20

The user split that episode up into 4 parts, so check them all out to see the whole thing, however, you can skip through the "hangover" tests. Pretty neat episode overall though.

I think that the Mythbusters did this test a while back. I also remembered they dimpled a car body like a golf ball and got a measurable increase as well. Might be able to find that information online somewhere.

Or just look at my post... Lol.

I think that myth has been busted for a while. If it were to make a difference with your MPG you wouldn't even notice it.

Think of it like tire pressure; its one of the most important things to check for safety/durability, but the 3% decrease in mileage is almost unnoticeable when you run under-inflated tires.

Way back a long time ago, there was an article about this flight in an Air Force publication. The story had it that one of the C-130 folks noticed in the flight manual that the range of the C-130 exceeded a then-current world record. He brought that to the attention of the Powers That Be. As part of the preparations for the flight there was a base picnic, during which many folks took great pains to wash and wax the airplane in hopes it would help. The quote from Wikipedia follows.

World's longest turboprop aircraft distance record[edit]

On 20 February 1972, Lieutenant Colonel Edgar Allison, USAF, and his flight crew set a recognized turboprop aircraft class record of 8,732.09 miles (14,052.94 km) for a great circle distance without landing. The USAF Lockheed HC-130H was flown from Ching Chuan Kang Air Base, Republic of China (Taiwan), to Scott AFB, Illinois in the United States. As of 2013, this record still stands more than 40 years later.