Ok, girls
you want a challenge to keep you interested in your Benz's ? Never mind doddling under the hood, doddle at what you feed it. Make your own fuel, biodiesel that is, pure fryer grease, converted to burn in any unmodified diesel engine.
Wanna learn how to do it right ?
http://journeytoforever.org/biodiesel_make.html Complete step by step. Once you get into it you'll not have time to get bored. You can make a little or make a lot, it's up to you and your needs and supply.
Have fun, burn clean.