Changing Your Vegetable Oil Filter

There is a direct correlation between pre-filtering and in-line filter life. The average life span of a filter will be 500-3000 miles (or possibly more). You will probably notice a decrease in power (and possibly surging) upon acceleration and hill climbing when it is time to change your filter. Vehicles equipped with an in-line vacuum gauge will show a dramatic increase in vacuum draw when the filter becomes restricted.

To change a fuel filter, make sure the engine is cool. Remove the filter and filter head from the heated coil assembly. Twist the filter clockwise to unscrew it from the filter head (Fig. 1). Be aware that the used filter will be full of fuel, which should be disposed of, appropriately (not poured into the new filter). For example, you can drain it into your vegetable oil pre-filter tank.

Priming new filter with fresh oil. Slowly pour oil through outer holes, not through the center.

Lubricating the filter gasket before installation with some oil

Installation of new filter

Fill your new filter (Note: clean fuel is pulled from the center hole, so fill slowly through outer holes) with clean fuel until the filter is full. This can be one pint of fuel or more. When the new filter is full of fuel, lubricate the outer seal with clean vegetable oil (Fig. 2) and carefully screw the filter back onto the filter head, making sure it's threaded properly. When the gasket on the filter makes contact with the filter head, tighten the filter only two thirds of a turn further (Fig. 3).Over-tightening will make the filter very difficult to remove and will not improve the seal. Hand-tighten only; do not use a filter wrench. Return the filter and filter head assembly to heat exchanger. Start the engine and purge for 20 to 30 seconds to flush any existing air from the lines.