Every time you manually switch from SVO/WVO back to diesel, if you are not controlling the return line, whatever fuel is in the lines between the valves and the engine is returned to the diesel tank. On most vehicles this is not a problem, and can even help add lubrication to the diesel tank, but if you are returning quite a bit of SVO/WVO to the diesel tank it can build up quickly. This build-up of unheated oil can, at the very least, clog filters and it can eventually cause carbon build-up in newer injectors.

Some newer vehicles that have sensors in the diesel tank are not allowed to have more than 2% of oil in the diesel tank, as dictated by the manufacturer.

These purge timers can be set to the amount of time it takes your engine to purge the SVO/WVO through the return solenoid. The timer is set to this amount of time, then when you switch from SVO/WVO back to diesel, it will keep the return solenoid to the veggie tank open and keep it returning to this tank until the timer runs out. By that time, the fuel lines will be filled with diesel and when the solenoid switches over, it will automatically return diesel to the diesel tank.

These timers come with installation directions, are pre-wired, and labeled for quick and easy installation. They are designed to be used with two 3-port solenoids. If your set-up uses a Pollak or other 6-port valve, you will need to put one 3-port valve between your diesel and veggie return lines. Instructions for this scenario are included.

One timer will keep the veggie oil out of the diesel tank. Two timers can be used to completely isolate your two tanks.

Note: When we convert vehicles, we normally use one timer because our tanks have the return line in the heating chamber, next to the fuel intake. This means that the first fuel coming out of the veggie tank has a little diesel in it, which has shown to extend the life of filters, and acts as a buffer, should you switch to veggie too early or if the oil is a thicker type than usual.

Back to Catalog