The importance of cleaning your fuel system

What is this polymerization?

 

.Polymerization is a chemical reaction in which smaller molecules will combine in chains to form larger molecules.  For the purposes of this article we are concerned with the
formation of vegetable oil polymers in the fuel system of your vehicle. Unfortunately
polymer formation is a naturally occurring process that is promoted by heat, air and
contact with certain materials and the environment in your vegetable oil tank can be the
ideal environment for growing polymer chains.

What causes polymerization?

 
Viscosity and heat transfer testing in the Greasecar lab
 

For the purposes of this discussion, heat, in addition to contact with air and certain
reactive materials will promote polymer formation in and around your fuel system.

Although any metal will generally promote polymerization, certain materials are more
reactive than others. Most commonly affected are carbon steel, zinc, brass, copper and
tin, however, despite the materials used, under ideal conditions SVO can polymerize on
nearly any surface.

Greasecar has been successfully using copper as a heat exchanger for nearly 10 years. Why copper when it's known that oil can polymerize on it? Not only is it extremely efficient at transferring heat from the coolant to the oil, it is also very resilient to abuse and vibration. The same coil made from a material such as aluminum would quickly fatigue and develop stress cracks which would compromise it's structural integrity. It is crucial to keep the coil’s exposure to air to a minimum. To do this you must keep your tank topped off, and your system in operation. Someone who uses their system infrequently and only occasionally tops off their tanks is bound to have problems somewhere down the line. This could excessive buildup which could get caught in the fuel system.

Despite all prior indications listed here, the reaction of polymerization in the vegetable oil does have some benefit; the chemical process can actually reduce the viscosity of the vegetable oil, as Greasecar found during viscosity testing.

Keep in mind that if you don't keep up with system maintenance, you stand the risk of affecting some original factory components that cannot be addressed. Injector lines, injection pumps and injectors all contain metals that can potentially react with the vegetable oil. For this reason, it is important to periodically address the potential accumulation of polymerization by a fuel system cleaning. As a preventative maintenance procedure, Greasecar can disassemble your fuel system, clean residues from the tank, and flush out your fuel lines. Doing this will help clean potential build up from the fuel system minimizing the possibility of polymerization-related breakdowns.

What does this mean to me?

Formation your fuel cap and accumulation of polymer sediment which can shorten fuel filter life.
Both of these scenarios can lead to power loss and fuel flow restriction when running on
vegetable In extreme cases when a quantity of fuel has been sitting in your Greasecar tank for
months changes turpentine smell to your fuel and a significant change in color and consistency, all of
which will effect it's suitablity as a fuel.

 

How can I clean polymers from my system?

When polymers form and accumulate on tank components or form sediment it is
necessary to physically clean these residues form the surfaces they are attracted to. A
fuel cap can be cleaned by removal and dis-assembly (Refer to article). When polymer
sediments accumulate in the bottom of the tank it is necessary to remove the hatch plate
on the top of your tank, drain the tank and wipe up the sediment.  If harder sediment scale
is found to be coating the heating coil or internal fittings it can be left in place as it is only
the loose material which will cause problems. The softer, rubbery polymers will form
sheets and can be peeled or scraped off.  Once you are satisfied that you have removed as
much loose polymer as possible you may re-seal and re-fill your tank.

 

What measures can I take to prevent this stuff from
forming in the future?


Polymer formation is unlikely to be completely eliminated, however there are things you
can do to slow down the reaction and minimize accumulation.
 
1. Always try to keep your tank topped up to minimize air in contact with your fuel.
2. Wipe up vegetable oil if spilled on top of your tank or around the filler area.
3. Wipe off your fuel cap regularly if you find lighter residues forming.
4. We have also found that adding up to 10% diesel to your vegetable oil can
substantially reduce the re-activity in your fuel tank.