What the Oil Filter Does...

You may take your oil filter for granted, but this small, inexpensive part of your vehicle's lubrication system plays a vital role in protecting the engine from premature wear. Each moving part in the engine and the cylinder walls requires clean oil for proper lubrication and lasting life. The oil filter cleans the oil as it passes through the filter element or filtering media. This prevents abrasive contaminants in the engine lubrication system from damaging engine parts.

The better you understand your engine's lubrication system, the more you'll appreciate the vital role your oil filter plays. When the engine is running, oil enters the oil pump through a screened intake. The screened intake -- or oil pick-up -- is located in the crankcase near the bottom surface of the oil pan. The oil is drawn through the screen intake and forced by the oil pump through the oil filter.

Oil from the main gallery is also fed through vertical passages to the crankshaft main bearings and through the crankshaft to the rod bearings. Oil thrown from the crankshaft, or sprayed from the connecting rods, lubricates the pistons and cylinder walls.

In a typical full-flow type oil filter, the oil flows into an inlet passage and then through the filtering element. After flowing through the filter element, the filtered or "clean" oil passes directly to the main oil gallery. In a partial-flow type filter, the oil returns directly to the oil pan.

Oil from the main gallery lubricates the camshaft and the camshaft bearings (and feeds hydraulic valve lifters if used in the engine). On non-overhead cam engines, oil is metered through the valve lifter to a hollow push rod that carries oil for the lubrication of the push rod pivot point, rocker arm pivots and valve guide.

Oil Filter Media

The media is the filtering material in the oil filter element. It essentially determines the efficiency, performance and useful life of the oil filter.

There are two basic types of filter media: the "paper" media and the "depth" type media. The primary features of the filter elements are:

Particle size retention (filtration efficiency)
Particle size retention is the measure of the degree to which the filter can retain particles of various sizes. NAPA Filters has developed optimum particle size retention quality in filter media by extensive engine wear tests including exhaustive testing of filters used in racing, and sophisticated laboratory tests. NAPA Filters media in the automotive full-flow oil filter is able to trap and hold essentially all the contaminant particles larger than 25 microns. (A human hair measures approximately 70 microns in diameter. An object that is 1 micron in size is .000039 inches in diameter.) Our filters also capture a high percentage of even smaller particles.

Dirt-holding capacity
Dirt-holding capacity is the amount of contaminant that can be removed and held by the filter until the filter ceases to function. The capacity of NAPA Filters filters is significantly larger than the minimum requirements to efficiently filter all the oil during the oil and filter change periods as specified by vehicle manufacturers.

Resistance to oil flow
NAPA Filters full-flow oil filters for automotive applications use arch-pleated, prescription-blended media. When new, the media with a maximized number of pleats has less than 2 psi pressure drop when filtering oil at a rate of 4 g.p.m. at normal operating temperature. This low initial restriction to oil flow protects the vital engine parts more effectively.

Parts of an Oil Filter

  • Gasket - provides exterior seal between the filter and engine at the engine mounting surface.
  • Mounting Plate - prevents deflection (movement) at the gasket sealing surface.
  • Inner Element Support - provides inner element stabilization and a positive seal between the inner element and the mounting plate to prevent the bypass of unfiltered oil.
  • Heavy gage steel plate provides for threaded attachment to the engine.
  • Upper End Cap - retains element end sealant and filter media, provides an outlet for clean oil, and provides structural rigidity to the pleated media.
  • Lower End Cap - retains element end sealant and filter media.
  • Arch-pleated, Prescription-blended Filter Media - provides a more than adequate filter area.
  • The element has a controlled porosity blended media to assure complete filtration of the oil.
  • Spiral-wound Center Tube - provides internal element support. The spiral design greatly reduces initial flow restriction when compared to other designs.
  • Coiled Spring - ensures a constant load on the inner element to maintain the seal between the upper element end cap, the inner element support, and the mounting plate even during pressure surge situations.
  • Filter Canister - encloses the assembly with a mechanically-locked double seam. The canister provides "flutes" at the closed end for ease of removal with an oil filter wrench.
  • Silicone Anti-Drainback Valve - Stays flexible in extreme temperatures, improves oil flow and keeps oil in filter to prevent engine destroying dry starts. Also provides lasting protection to meet new vehicle manufacturers longer recommended oil change schedules. Nitrile valves can harden and become ineffective over time.

Some NAPA Filters full-flow filters include anti-drainback and/or filter by-pass valves. These types of filters are identical to full-flow filters, except that a by-pass valve replaces the inner element support and an anti-drainback valve has been added. The Anti-Drainback Valve prevents oil from draining out of the filter inlet holes when the engine is shut off. It also provides seal between clean and dirty oil at the upper end cap. This is necessary in applications where the oil filter is mounted in a horizontal or inverted position.

The Filter By-Pass Valve
If a NAPA Filters full-flow filter becomes "clogged", or excessively restrictive to oil flow, the filter by-pass valve ensures continued engine lubrication by allowing the oil to by-pass the filter. Some vehicle manufacturers have the by-pass valve built into the oil filter mounting unit (located on the engine).

Other vehicle manufacturers require full-flow filters have the by-pass valve built into the filter itself. All NAPA Filters oil filter types recommended for these particular applications include the by-pass valve assembly in the filter.

 By-pass Valve Assembly -- spring loaded valve assembly that allows oil to by-pass the element under high-differential pressure conditions such as cold oil and/or excessively contaminated media. This allows lubrication of the engine, but without full-flow filtration.

What the Air Filter Does...

Like oil filters, air filters can be easily overlooked. They often don't get replaced until they are absolutely clogged with dirt and soot. To help keep a vehicle running well, and to protect the intake system from premature wear, it's important to change the air filter in your vehicle at the proper intervals.

The air filter removes soot, carbon, abrasives and other contaminants from the air before the air mixes with fuel in the engine induction system. If allowed to get inside the engine, even microscopic dust particles can damage cylinder walls, pistons and piston rings. Since as much as 10,000 gallons of air must pass through the air filter for every gallon of fuel the engine burns, NAPA Filters quality air filters -- available for virtually every vehicle -- lengthen engine life by preventing the introduction of damaging foreign particles to the fuel mix. Our comprehensive line of quality air filters encompasses various applications, both stationary and vehicular for both on and off-road applications.

Panel Element Air Filter; Linear path through the filter for low air flow restriction. Specially formulated adhesive, helps form our exclusive pocket pleat for the filter media. Urethane soft sealing gasket molded in place on the filter element. Mesh support screening which is molded in place with the element paper (if applicable).

Radial Air Filters; Mesh screen on the inside wall diameter for element strength and media protection from back-fire. Mesh screen on the outside diameter for element strength. Heat-resistant plastisol with specially-designed crush seals on the top and bottom walls. Adhesive seal joining the media ends.

What the Automotive Fuel Filter Does...

Fuel filters are essential in helping to protect fuel system components from contaminants that may be in the fuel. These contaminants can plug fuel injectors or carburetors, causing engine malfunction and deterioration. Dirt, rust, scale and water are the major impurities present in fuel. These impurities can originate from dirty and rusty service station storage tanks and, as the vehicle ages, from corrosion within the fuel system components.

All of the fuel that enters the engine must first pass through the fuel filter. Which means the high efficiency provided by NAPA Filters fuel filters is vital for long and trouble-free fuel system and engine life.

Diesel Fuel Filters
Fine particles, free water and emulsified water must be removed from diesel fuel before it passes through the fuel injection system. Fuel from the fuel tank is routed through the filter where contaminants are removed. If the filter is a fuel / water separator, the fine particles remain trapped in the filter media while the water droplets come together and fall to the bottom of the filter. NAPA Filters fuel / water separator filters are equipped with a drain at the bottom of the filter to drain this water from the filter.

NAPA Filters offers high quality, high efficiency fuel filters for medium and heavy-duty trucks, as well as farm, construction, mining and other equipment applications.

Features

  • Both spin-on and cartridge-type fuel filters available.
  • Spin-on fuel filters feature built-in gaskets.
  • Some spin-on filters, fuel / water separators, have a drain plug.
  • Designed to prevent accidental interchange of primary and secondary elements when used with dual filter systems.
  • All fuel filters are designed to withstand minimum internal differential pressures of 75 psi.

Benefits

  • Unmatched fuel cleansing performance.
  • Spin-on filters reduce the possibility of misinstalled cover gaskets.
  • Long life and the possibility of extended service intervals.
  • Effective, easy draining of excess water with filters equipped with the drain plug.
  • Quick, easy filter replacement.
  • Materials, design and construction that ensure NAPA Filters fuel filters provide excellent performance under all types of operating conditions.

What the Coolant Filter Does...

Properly installed and maintained, coolant filters help to provide:

  • A clean, well-functioning engine cooling system.
  • Proper engine heat dissipation.
  • Engine efficiency through improved heat conductivity.
  • Method to introduce necessary Supplemental Coolant Additives (SCA's) when required.

Coolant filters mechanically filter the coolant through a fine media, removing impurities such as sand and rust particles suspended in the cooling system. The coolant filter also conditions the coolant by softening the water to minimize scale deposits, maintains a neutral to slightly alkaline condition in the coolant, and prevents rust.

Corrosion Inhibitors
In some applications, a corrosion inhibitor (SCA) is placed in the coolant filter. This inhibitor dissolves into the coolant, forming a protective film on all metal surfaces in the cooling system. The inhibitor is a combination of chemical compounds blended to provide corrosion and cavitation erosion protection, pH control and water softening.