I use a pretty light mixture just to make the grease stretch further and to prevent any gelling, especially this time of year. To ensure it mixes well before I pour it in the tank, I usually mix equal parts soybean oil and dino diesel in a 5 gallon gas can, then pour that in the tank on top of whatever diesel is in there. So once in the tank, at most I've probably got 20 percent soybean oil in there. But this is enough to smooth out the idle and clean up the exhaust odor noticeably.

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'81 300TD turbo <<sold 12/05 to another diesel nut