I thought I'd pass along some information that I have come across.

My current day job is as an editor on the Canadian Journal of Chemistry. My background wasn't in Chemistry so a lot of the material is way over my head. However, I have edited quite a few papers on the general topic of Tribology. It is an aspect of surface science having to do with surfaces that rub together. Our daily lives are filled with things that rub together, especially in our cars.

Developing and testing motor oils is one area of Tribology and you might be interested to know that one of the world's foremost labs in this area is the Chemistry department at the University of Western Ontario in London. That field of study falls into the realm of molecular physics (chemical physics) both because a lot of what happens at frictional surfaces has to do with atomic behaviour and because the analysis tools of the surfaces (such as high intensity X-rays) is stuff that physicists know a lot about.

I edited a paper last month about research being done into replacing phosphorus-based additives in motor oil. Such additives are commonplace, possibly used in every oil we buy. Replacing phosphorus is important because it is incompatible with the kinds of catalytic converters that will be used in the new direct-injection high-tech diesels (FINALLY) coming our way to North America. If you use the current oils in these things, you'll wear out your converter prematurely.

I was reading about the new diesels coming in the '08 VW's. They are talking about mileage figures in the 4-5 litres per 100 km range, with very high torque and hp numbers, music to my ears. Although they exhibit extended oil life, they WILL REQUIRE special oil (with possible warranty ramifications).

Something else about diesels that isn't talked about much is the thousands of dollars in damage that you can if you accidentally pour gasoline into a diesel's tank. It's easy to do because the size of the pump nozzle does not prevent it. I'd hate to think what would happen if they started renting out diesels in large numbers. People would screw them up all the time. If you are a two-car family and they're both Golf's, say, one a TDI and the other not, don't fill your tank until after you've had that morning coffee.

On your second issue, being a formal diesel owner, I was quite intrigued when our local National Car Rental location purchsed 5 brand new TDI Jetta's a couple of years ago. I rented one and even though it had a slushbox, came away quite impressed with the power and mileage of the TDI compared to my straight TD.

I mentioned how happy I was and told them I looked forward to the chance of renting one again. The owner told me not to bother. He had purchased 5 of them and the other 4 had the engines destroyed by renters filling them with gas. He was never buying them again!!!