Earlier I was watching a neighbour who apparently was pouring water from a 1 gallon transparent plastic can into his fuel tank. I thought, "That's a cheap way to run a car!" When he had finished, I saw that the liquid was going into a hole *next* to the fuel filler. What was going on there? Maybe it's windscreen wash fluid. Some cars have a common tank for front and rear, but he was putting rather a lot in, and it was colourless, and usually you put blue additive in.
I did a few searches on the Internet, and found out that, in all probability, what he was adding was "Addblue" (aka diesel exhaust fluid) to his diesel Audi A6. Apparently nowadays diesel vehicles need this extra stuff to reduce pollution.
What a faff! Apparently this car has a 17l tank which lasts 9,000 miles. Do filling stations have pumps for this? How much does it cost? Why do people still bother with diesel if they have to go to all this trouble?
I hired a diesel van about five years ago, and they didn't say anything about this stuff. When was this a requirement? Maybe the hire company put it in when required.
Why is it called "Addblue" when it's colourless?
Apparently it's 32.5% urea and 67.5% deionized water. Isn't that piss? (I recall an old joke about a nun filling her petrol tank from a chamber pot.)