Gulf Coast Filters Specializing in Bypass Oil filters, Fuel filters, Hydraulic filters and Custom filtering



Gulf Coast Filters

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High Quality Filters
for Over 30 Years!




The following installation instructions and general information are intended for the use of our trained personnel, professional mechanics, or other persons thoroughly familiar with large engines.

The GCF Oil Filter is a by-pass filter. It requires a suitable mounting location (preferably vertical), a pressure source and a return for the oil to the engine. In choosing a mounting location. Keep in mind the future servicing and repair requirements of the engine.


To answer this question, it is important to review the full-flow and by-pass filter systems.

In the full-flow system, all the oil that lubricates the engine is first pumped through the full-flow filter. Since this amount of oil is quite large, 10 to 20 quarts in a V8 car engine and much more in a large diesel engine, the full-flow must be porous (somewhat like a sieve) so it will not restrict this large volume of oil.

The advantages of the full-flow system are:

It protects the bearings and all other moving parts of the engine since the oil has to go through it first. It is especially useful during break-in when close tolerance parts are “wearing in”. By filtering all the oil used in lubricating the precision parts, the larger particles that could seriously damage the engine are removed EXCEPT during start-up. If the oil is too cold or thick to readily flow through the filter, the pressure relief valve opens and allows unfiltered oil to lubricate the engine. Also, this valve opens when the full-flow filter becomes clogged. The reason for this is that dirty oil is better than no oil.

In the by-pass system, the oil is regulated through the filter in a very small amount and then returns directly to the oil pan. This filtering system filters a small percentage of the oil and refreshes the engine with oil that has passed slowly through a much denser element than the full-flow element. Since it filters at a very slow rate, and it is not responsible for supplying oil for lubrication, it is possible to insert a very dense element that will trap the microscopic particles that grind away the precision moving parts of the engine. With the proper element, it also can remove sludge producing contaminants (mostly water and carbon particles). The disadvantage, of course, is that only a small portion of the oil is filtered at a time. An interesting note is that many industrial engines still come factory equipped with only the by-pass filter system.


Both! If your engine is equipped with a full-flow filter system leave it intact to do its designed function of protecting the moving parts of the engine. Add a quality GCF by-pass filter to keep the oil CLEAN!

Highway Use - Change filter element every 10,000 miles.
Stop & Go Use - Change filter element every 5,000 miles.
Stationary or Boat Use

Engine Size (HP)

Number of Filters Required

Change Interval (Hours)

Up to 250

1 single


250 to 500

1 double


500 to 1000

2 doubles


1000 to 1500

3 doubles


1500 to 2000

4 doubles


+ Indicates Model 0-2

Routine operation. Other than normal driving conditions require more frequent service. 
Rule of thumb: large engines require more service than small engines.

 Powerstroke O-1 Installation
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Duramax O-1 Installation
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Dodge Cummins Installation
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Gulf Coast Filters
P.O. Box 2787
Gulfport, MS  39505