The fuel filter in your 1998 Mazda 626 is required to not only filter out contaminates like rust and sediment, but also to supply the injectors with enough fuel pressure and volume to meet the needs of the engine under all load conditions. This high pressure filter features a large filter area to meet those needs. Replacement of the filter can be done by the average home mechanic in about an hour using basic hand tools.
Remove the air filter housing for access to the fuel filter located behind it on the frame. Loosen the clamp attaching the intake duct to the throttle body and un-clip the retaining clips on the upper filter box. Un-plug the vacuum lines from the filter housing, and rotate the upper filter box until it slides off the throttle body. Remove the 10-mm bolts, attaching the lower filter housing to the frame of the car, with a 10-mm socket and socket wrench. Remove both pieces from the engine compartment. The fuel filter is the black cylinder shaped part attached to the fuel lines.
Loosen the upper fuel line clamp with a screwdriver and twist the fuel line on the fuel filter with a pair of needle nose pliers to break it free from the filter. Then remove the line by twisting back and forth while pulling the line. Loosen the retaining bolt on the fuel line bracket with a 10-mm socket and socket wrench. Slip the filter out of the bracket. Loosen the remaining (lower) fuel line clamp and remove the fuel line in the same manner as the upper was removed. Discard the old fuel filter.
Install the lower fuel line onto the filter and tighten the fuel line clamp. Push the new filter up through the bottom of the bracket and tighten the retaining bolt. Install the upper fuel line on the filter and tighten the fuel line clamp.
Reinstall the air filter housing and tighten the air duct clamp that attaches the duct to the throttle body. Turn the ignition key to the run position and back to the off position three times to prime the filter. Start the engine and check for leaks.
