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What Happens If a Fuel Filter Is Put on Backward?

by Jay Motes

Automotive fuel filters come in a variety of designs and are located in different places. While some fuel filters are made to prevent installing them backward, some can be installed backward and may, or may not, create problems.

Symptoms

A fuel filter put in backwards may restrict or stop the flow of fuel to the engine. If, after changing a fuel filter, the engine suddenly displays a loss of performance, the filter should be inspected for proper installation.

Other Problems

Worse than performance problems, a fuel filter that was installed backward may cause problems that do not produce noticeable symptoms. A backward fuel filter may restrict fuel to the engine, but the restriction is made up by the fuel pump. This will result in increased wear to the fuel pump and may cause pump failure. While fuel filters are inexpensive and easy to change, fuel pumps are expensive and difficult to change.

Correct Installation

Fuel filters that can be installed backward have printing or symbols on the filter to indicate which way the filter should be installed. If there is any concern that a filter has been installed backward, the filter should be removed and inspected to assure proper installation.

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