Kreen is made by Kano Labs @ www.kanolabs.com
I've been using it for about 6-7 months now. It's not like any other cleaner I have used. It's a dirivative of one of their other products, Kroil---which is the best nut/bolt loosener I've used. I've had many customers use WD40 as a lubricant. While it has some lubricating properties, it's really a solvent---if you get reral greasy, spray WD40 on your hands before using any cleaner---it will dissolve most of the grease.
The consistency of Kreen is that of WD40. The way I think it works is that it gets into all the nooks and crannies the the detergents in the oil miss and gets the crapola suspended in the oil before it evaporates in a short time. I have used it in all my cars, trucks and generators. You also put it in your fuel and it decarbonizes and cleans it. After running 50 gallons of treated fuel thru my Onan generator, I had a TREMENDOUS amount of soot at the exhaust point. The engine was more quiet and ran better.
The same time I put it in the oil of my Golf I also put it in the fuel---I noticed more power. The current tank is treated with DEE-ZOL and I have noticed a decrease in power. I have noticed increses power in the gas vehicles as well. Mileage is tough to calculate since my fuel comes from my own tanks(the local gas stations' cheapest gas is $2.12.9). I like it so much, I went thru 2 five gallon pails in the first 6-7 months and just received a 55 gallon drum.