TUBE AS 5001094 - Caterpillar

Illustration 1 g03525941
Example of a fuel filter assembly
When the secondary fuel is restricted due to the buildup of contaminants, a plugged filter warning light, if equipped, is activated in the operator compartment. Replace the filter immediately in order to avoid fuel system contamination. If the filter is not changed upon the indication of excessive restriction, the pressure across the filter continues to rise and pushes contaminants that were trapped in the filter media through the filter and into the clean fuel. Contaminated fuel can cause serious fuel injector wear and damage.
Note: Electric Priming pumps are recommended to pre-fill the secondary fuel filter with clean fuel when a filter is changed to help start the engine. Refer to this Special Publication, "Priming Pumps".Priming Pumps
In order to help prevent hard starting after the installation of new fuel filters, purging air from the fuel system is necessary prior to engine startup. Priming pumps remove this air from the system by pumping fuel through the fuel system. Priming pumps are typically installed on or near the fuel water separator, although in some cases priming pumps are remotely mounted.Caterpillar offers two kinds of priming systems:Electric Priming Pumps - Electric priming pumps work by either pushing a switch, or automatically run when the system is cycled on. These pumps take 2 to 6 minutes to prime the fuel system.Hand Priming Pumps - Hand priming pumps are manually operated to prime the fuel system.Caterpillar recommends against the practice of pre-filling fuel filters prior to filter installation. Doing so can introduce debris into the fuel system which can cause harm to fuel injectors and result in downtime and increased maintenance costs. Using a priming pump avoids the introduction of this debris by ensuring the fuel has been properly filtered before the fuel reaches critical components of the fuel system.Note: Electric Priming pumps are recommended to pre-fill the secondary fuel filter with clean fuel when a filter is changed to help start the engine. An electric priming pump contains another filter so that all the fuel supplied to the system has been pre-filtered. This type of pump reduces the time and effort needed to fill a new fuel filter compared with the manual priming pumps.