How-to: Dodge Ram Truck Air
Filter and Fuel Filter Service
factory gauge measures air flow at the air cleaner box. This indicates the air filter's ability to move
air. As the filter clogs, the gauge moves to the red zone.
Air and Fuel Filtration
Air filtration is
crucial to an engine's performance and lifespan. A clogged air filter prevents adequate air flow
and increases fuel consumption. If the filter does not seal properly, abrasive material seeps into the air
stream and damages the pistons, rings and the valves.
Years ago, when
truck engines were all carbureted (gasoline) or mechanically fuel injected (diesel), a clogged air cleaner was
obvious: The engine failed to perform well or used excessive amounts of fuel. Today, with EFI/MPI on
both gasoline and diesel engines, performance with a dirty air filter is not that easy to spot—until the
filter clogs grossly!
"How often do I change
my air or fuel filter?" many ask. This is a difficult question to answer, since both fuel and air flow are quickly
affected by contaminants. For the Dodge-Ram truck that drives down washboard gravel roads all day long, an air
filter can clog rapidly. A full day's exposure to alkaline dust can render a pleated paper air filter useless.
Dust conditions dictate filter needs.
Note: Most air filters require
regular visual inspections. For some later model Dodge and Ram truck engines, an air-flow gauge allows quick
spot-checks of the filter's ability to flow air.
service intervals are also difficult to determine. Of course, mileage-based OEM recommendations make sense. You
will find these intervals listed in the owners manual or a Service Manual for your truck.
There are additional variables to consider, too.
Diesel fuel, for
example, can contain high levels of water and particulates. In some regions, diesel fuel and fuel filters
suffer from bacterial contamination.
With both gasoline and
diesel fuel filters, the pleated paper will swell when exposed to water. (That's how the
filter prevents water from damaging the fuel distribution system and fuel injectors.) As little as one bad
tankful of water-dense fuel is enough to swell and clog the filter. Often, with little or no notice, the fuel
supply shuts off!
Given the variables,
it's always wise to change air and fuel filters at recommended intervals—or sooner! In your Dodge-Ram
truck owners manual, you will find "A" and "B" service schedules listed. These are the minimal time
intervals for service.
If you tow or drive in
dusty environments, use the severe-duty service schedule. Unless you drive your truck without a load and
along dust-free interstates, the air filter requires steady attention. For fuel filters, always use the severe
duty service interval.
Note: When traveling to remote
areas, always carry an extra fuel filter and air filter element—bring the tools necessary for changing the
How-to: Servicing a Dodge-Ram Truck's Engine Air
Modern Dodge and Ram truck engines use pleated paper air filter
elements. These filters, contained in a plastic air box, are accessible and readily
1. Commonly, the Dodge-Ram truck
air boxes have a removable top with spring hold-down clips. This
illustration shows a spring clip on the '05 Dodge
Ram 3500 turbo-diesel's air cleaner box. There are usually several clips. Go around the box,
loosening clips carefully.
2. For this air box, it is easier to remove the top by first loosening the air inlet hose
(upper left). This view is the topside of the old air cleaner, which looks clean. See the dirty
air filter (further up the page). This is the same filter! Always remove and inspect the
intake side of the filter.
3. This is the unfiltered area of the air box.
Fortunately, the filter element prevents the abrasive debris and road dirt from entering the engine! This
illustrates how important it is to make sure the air filter element seals against the air box
4. To prevent quick contamination of the new air filter element, clean out the air box during the
filter service. A clean rag and solvent will remove the sooty debris. Dry out and vacuum the box before
installing the new air filter.
5. Our choice for quality filtration and
maximum engine protection is the Mopar® product line. For our '05 Dodge
Ram 3500 turbo-diesel, we turn to the Mopar® extreme service, OEM replacement
Mopar® Performance offers specialty aftermarket filters and systems
designed for racing and severe environments, including ram-air induction.
6. This is a unique option available for severe
duty air filtration. Mopar® offers this as an OEM replacement air filter
element. Many truck owners do not know about it...For the '05 Dodge Ram Cummins turbo-diesel application, the
Mopar® quick reference number is MO-249. (The full Mopar number is
Note: See your Chrysler Group or Dodge Ram Truck dealer. Request the severe-duty option if available for
your model and engine application!
7. The difference between the MO-249 filter and
the standard OEM filter (top) is dramatic. Added thickness and dense pleats mean far more surface area.
This allows the filter to accumulate more contaminants and provides a much longer service life. For long trips
across dirt and gravel roads, a severe-duty filter makes the best sense.
Place the new filter in the air box. Place the lid carefully back into place, making sure the lid seals
around the entire filter and air box flange. Fasten the air box spring clips then position hoses and wiring back at
their original locations. Be sure the lid fits flush and seals completely.
8. This is the inlet hose clamp. The hose is
now in its original position on the air box lid. When loosening and tightening the clamp, be certain to
restore the hose seal. Prevent dirt from entering the air stream at the engine side of the
Note: As a safety precaution, carefully position the hose and clamp at the OEM location.
In this position, the clamp will conform snugly to impressions and contours, sealing the hose against the air
Diesel Fuel Filter Change
Chrysler-built trucks with gasoline engines and EFI/MPI may not have a fuel filter. (See your truck's owner
manual or a factory OEM Service Manual.) Often, the high output fuel pump has a "sock" filter at its
in-tank pickup. There may be a filter/regulator device that does not require periodic service. Such devices usually
last the service life of the fuel pump or the pressure regulator.
Some models do use a replaceable filter.
In the case of Cummins turbo-diesel engines, there is always a serviceable fuel filter. Diesel fuel, by
its nature, requires ample filtration and even a water trap. This filter must be replaced at regular intervals. If
not, the truck's engine will lose power or stop running without warning.
Caution: Diesel fuel filters often fail
due to water content in the fuel. A single fill-up at the wrong filling station can lead to a clogged fuel filter.
It is wise to carry a spare fuel filter on long trips. Know how to replace the filter; bring the
Note: One way to prevent accidental
spillage of dirty fuel into the deliver spout of the filter is to drain the fuel filter/water separator
housing before removing the filter. The fuel canister has a drain valve for removing excess water. You can also use
this valve to drain the housing of fuel and contaminants before changing the filter cartridge or performing service
on the canister, valve or water-in-fuel sensor.
How to Drain the Fuel Filter
1. A drain hose is located at the bottom of
drain valve. Place drain pan under drain hose.
2. With engine not running, rotate drain valve
handle counter-clockwise (rearward) to OPEN and DRAIN position. Hold drain valve open until all water and
contaminants have been removed and clean fuel exits.
3. If drain valve, fuel heater element or
Water-In-Fuel (WIF) sensor is being replaced, drain housing completely.
Dispose of drained fuel properly.
4. After draining
operation, rotate valve handle clockwise (forward) to the CLOSE position.
1. The '05 Dodge Ram Cummins model has an
accessible fuel filter canister. Wipe away any debris from the canister lid area before removing the cap! The
plastic cap's built-in hex fitting is 1-1/8" size. Here, a socket and rachet turn the cap
counter-clockwise to loosen it. This is plastic; use care not to damage or round off the
2. Want OEM dependability like your Dodge-Ram
truck had when new? Use the Mopar® Cummins-rated fuel filters. Make no
Note: Use the
replacement filters recommended by both Chrysler Group and Cummins. Carry spare filters for backcountry travel and
3. This filter is Cummins-rated for the turbo
diesel. The package includes a new sealing gasket. Follow the provided instructions and carefully fit the filter
into the cap clips. The lid clips are plastic and become brittle with age. Twist the filter sideways for removal,
using minimal force to protect the tabs...Lube the O-ring as described in the new filter's
Caution: Keep the cap and filter free of debris as you install it in the fuel canister. Tighten with a
box-ended wrench or socket and ratchet. Torque as specified, this '05 cap requires 25 ft-lbs, do not
Note: If there is no torque
specification for your fuel filter cap, make it snug enough to compress the new O-ring and stay securely in place.
Being plastic, do not over-tighten. Always wipe away spilled fuel and check for fuel leaks.
Need to Prime the Fuel System After the Filter
the filter, you may discover that the "prime" is gone on the low-pressure pickup side of the system. (The
engine will not start due to lack of fuel in the system.) This requires priming, and on Dodge
Ram/Cummins systems like this 2005 Dodge Ram 3500, the system can be primed by the Chrysler recommended method
below. Read these notes carefully and pay close attention to the procedures and safety requirements. If this
procedure does not work, see the additional steps provided:
STANDARD [FACTORY] PROCEDURE - FUEL SYSTEM
A certain amount of air becomes trapped in the fuel system when fuel
system components on the supply and/or
high-pressure side are serviced or replaced. Fuel system priming is accomplished
using the electric fuel transfer (lift)
pump. Servicing or replacing fuel system
components will not require fuel system priming.
The fuel transfer (lift) pump is self-priming: When the key is first
turned on (without cranking engine), the pump
operates for approximately 1 to 2 second and then shuts off. (Note: When
ambient temperatures are cold enough to
cause the intake air heaters to operate, the fuel lift pump will operate during the
entire intake air pre-heat cycle).
The pump will also operate for up to 25 seconds after the starter is quickly engaged,
and then disengaged without
allowing the engine to start. The pump shuts off immediately if the key is on and the
engine stops running.
1. Turn key to CRANK position and quickly release key to ON position
before engine starts. This will operate fuel
transfer pump for approximately 25 seconds.
2. Crank engine. If the engine does not start after 25 seconds, turn key
to OFF position, and leave it off for at least
5 seconds. Repeat previous step until engine
3. Fuel system priming is now
4. Attempt to start engine. If engine will not start, proceed to
following steps. When engine does start, it may run
erratically and be noisy for a few minutes. This is a normal
CAUTION: Do not engage the starter motor for more than 30 seconds at a
time. Allow two minutes between
5. Perform previous fuel priming procedure steps using fuel transfer
pump. Be sure fuel is present at fuel tank.
6. Crank the engine for 30 seconds at a time to allow fuel system to
WARNING: THE FUEL INJECTION PUMP SUPPLIES EXTREMELY HIGH FUEL PRESSURE
TO EACH INDIVIDUAL
INJECTOR THROUGH THE HIGH-PRESSURE LINES. FUEL UNDER THIS AMOUNT OF PRESSURE
PENETRATE THE SKIN AND CAUSE PERSONAL INJURY. WEAR SAFETY GOGGLES AND ADEQUATE
CLOTHING. DO NOT LOOSEN FUEL FITTINGS WHILE ENGINE IS
WARNING: ENGINE MAY START WHILE CRANKING STARTER
These steps and cautions are factory recommended
for professional service technicians. If you follow them correctly, you can safely prime the fuel system on a
later Dodge Ram Cummins truck equipped with an in-tank priming pump—like our 2005 Dodge Ram
Earlier Dodge Ram/Cummins Fuel System Won't Pick Up Prime? Try the "Bump-Key"
Later trucks like our '05 model have a
priming pump at the fuel tank that responds to the factory priming procedure shared above. On earlier engines
without the priming pump at the fuel tank, you can also lengthen the pump priming duration by "bumping"
the key switch to the Start position.
On earlier Dodge/Cummins trucks,
try lightly bumping the key to the Start position and quickly releasing the key to the On position—do
this twice in a row without allowing the engine to fire. When the key releases to the On
position, this should activate the pickup pump for a 25-second or so interval. Repeat this priming procedure
as necessary, using the light "bump start" approach without actually allowing the engine to fire.
Once you get the sequence down, you can quickly cycle the electric "pickup" fuel pump to prime the entire fuel
This comes in very handy if you do
field injector emergency repairs. It also works when you completely run the engine and fuel
tank out of fuel or clog up a fuel filter. After you change the filter cartridge, if
the engine has lost prime, try this method. Use caution to preserve the starter motor and
Caution: If necessary, allow the fuel pump to
cool between pump cycles. Do not damage the fuel pump when trying to prime the engine! Make sure there is
unrestricted fuel flow from the tank, through the lines and through the fuel