We have been testing the effects of both auto and aviation fuels on the fuel gauges we manufacture. After three weeks of testing, indications were that the aviation fuel did not deteriorate the material of the gauge or cause it to expand. However, the auto fuel caused the plastic material to discolor and enlarged the center hole by 0.012.
Auto fuel with 10% ethanol had different effects. After 10 days, this fuel mixture caused a dramatic change in the fuel gauge to the point the marker could not pass through the center of the fuel gauge. The use of auto fuel containing ethanol did cause the inside of the gauge to discolor and swell so that the red marker did lock up due to the expansion of the material. Ethanol will completely destroy the gauge.
When you purchase one of our fuel gauges, we clearly state that these gauges are not to be used with auto fuel. If you have a problem with one of our gauges, it is probably the result of contamination by auto fuel.