Do not use anything BUT Elsbett. ESPECIALLY not in a tdi. Even frybrid, if they're even still selling kits. I had an 87 jetta with a great Ip, strong turbo diesel, and both a greasecar and frybrid systems failed. Leaked the coolant out, & almost killed the engine. (Had to replace the head gasket as naturally this overheated the engine very quickly, not to mention contaminated the fuel.) I don't even know why people mess around with any of the U.S. kits, and especially anything with two tanks that diverts that much coolant all the way to the back of the car, and uses fittings and hoses that will leak eventually & contaminate. They are way too complicated & don't even address half the issues needed when running wvo. The Elsbett people are the only ones endorsed by the German auto makers (of course not their clueless U.S. offices unfortunately) and pretty much started this whole thing over 30 yrs ago. And after having theirs for almost 2 yrs, I've never had a failure, never an issue. I had issues 3 weeks into my American 2 tank systems. And with this system you start & go, no purging, no start up heat & switch, etc. It's like it's native to the car, just start & go. They've been bought by a British company, but the original people are still in business and have U.S. offices (with Americans running the operations.) Their kits are comparable in price, and they'll install too for an extremely competitive price. We buy these cars for German simplicity & engineering, so you might as well buy a kit that is designed with those ideals. The main thing is, they don't only address heating (which they do very simply & effectively) but also the most important part, which is widening the fuel lines & injector holes. No u.s. kit makers even mention this. They don't even think about this!! Unbelievable. It's no wonder so many people report failures using wvo. Not with elsbett setups. I forget the name they're doing business under, but do a search for Alexander Noack. One of the original founders. He's still doing business worldwide & travels the states often to arrange installing kits.
. I'm not interested in using used oil because of the work involved in filtering it. However, no matter, as I said, I'm going in this direction only as insurance from having to endure another fuel shortage as in the 70's or ridiculous prices at the pump 
