GHG17 DD Medium Duty Operators Manual 4. Discard the prefilter. 5. Inspect inside the housing for any large debris; clean housing as needed. 6. Discard the prefilter cap seal ring. Installation of the Fuel Prefilter Install the fuel prefilter as follows: NOTE: If a filter service is being performed, replace all other filters before priming. 1. Install a new prefilter cap seal ring on to the prefilter cap. 2. Snap new prefilter into the prefilter cap. 3. Apply a thin coat of petroleum-based lithium grease to the prefilter cap seal ring and the prefilter seals (1). All information subject to change without notice. 89 DDC-SVC-MAN-0192 Copyright © 2017 DETROIT DIESEL CORPORATION