1998 DODGE RAM 1500 Fuel pump

Once a Month
²Check tire pressure and look for unusual wear
or damage.
²Inspect the batteries and clean and tighten the
terminals as required.
²Check the fluid levels of coolant reservoir, brake
master cylinder, power steering and transmission
and transfer case (if equipped), add as needed.
²Check Filter MinderŸ. Replace air cleaner
filter element if necessary.
²Check all lights and all other electrical items for
correct operation.
At Each Oil Change
²Change the engine oil filter.
²Inspect the exhaust system.
²Inspect the brake hoses.
²Inspect the CV joints (if equipped) and front sus-
pension components.
²Check the automatic transmission fluid level.
²Check the manual transmission fluid level.
²Check the coolant level, hoses, and clamps.
Tire Rotation
²Rotate the tires every 7,500 miles (12 000 km).
Engine Oil Change Chart Notes
²LTier 1 EPA (250 hp or 305 hp) Engines Only
(see engine data label for your engine type)
²² California LEV (235 hp) Engines Only (see
engine data label for your engine type)
Schedule ªBº
Follow schedule ªBº if you usually operate your
vehicle under one or more of the following conditions.
²Day or night temperatures are below 0É C (32É
F).
²Stop and go driving.
²Extensive engine idling.
²Driving in dusty conditions.
²Short trips of less than 16 km (10 miles).
²More than 50% of your driving is at sustained
high speeds during hot weather, above 32É C (90É F).
²Trailer towing.
²Taxi, police, or delivery service (commercial ser-
vice).
²Off-road or desert operation.
Miles 3,750 7,500 11,250 15,000 18,750
(Kilometers) (6 000) (12 000) (18 000) (24 000) (30 000)
Change engine oil and engine oil filter. X² XL²X²XL²X²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XX
Inspect water pump weep hole for
blockage.X
Replace fuel filter element. Clean the water
in fuel sensor.X
Change rear axle fluid. X
Change front axle fluid (4X4). X
Inspect brake linings.X
Inspect and adjust parking brake if
necessary.X
DRLUBRICATION & MAINTENANCE 0 - 13
MAINTENANCE SCHEDULES (Continued)

Miles 22,500 26,250 30,000 33,750 37,500
(Kilometers) (36 000) (42 000) (48 000) (54 000) (60 000)
Change engine oil and engine oil filter. XL²X²XL²X² XL²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XXX
Inspect drive belt, replace as required. X
Inspect fan hub. X
Inspect damper. X
Inspect water pump weep hole for
blockage.X
Replace fuel filter element. Clean the water
in fuel sensor.X
Change rear axle fluid. X
Change front axle fluid (4X4). X
Check transfer case fluid level (4X4). X
Drain and refill automatic transmission fluid.
Replace filter and adjust bands.X
Miles 41,250 45,000 48,750 52,500 56,250
(Kilometers) (66 000) (72 000) (78 000) (84 000) (90 000)
Change engine oil and engine oil filter. X² XL²X²XL²X²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XX
Inspect drive belt, replace as required. X
Inspect water pump weep hole for
blockage.X
Replace fuel filter element. Clean the water
in fuel sensor.X
Inspect brake linings. X
Inspect and adjust parking brake if
necessary.X
Change rear axle fluid. X
Change front axle fluid (4X4). X
0 - 14 LUBRICATION & MAINTENANCEDR
MAINTENANCE SCHEDULES (Continued)

Miles 60,000 63,750 67,500 71,250 75,000
(Kilometers) (96 000) (102 000) (108 000) (114 000) (120 000)
Change engine oil and engine oil filter. XL²X²XL²X² XL²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XXX
Inspect drive belt, replace as required. X
Inspect fan hub. X
Inspect damper. X
Inspect water pump weep hole for
blockage.XX
Replace fuel filter element. Clean the water
in fuel sensor.XX
Inspect front wheel bearings. X
Change rear axle fluid. X X
Change front axle fluid (4X4). X X
Inspect brake linings. X X
Inspect and adjust parking brake if
necessary.XX
Drain and refill transfer case fluid (4X4). X
Drain and refill automatic transmission fluid.
Replace filter and adjust bands.X
Miles 78,750 82,500 86,250 90,000 93,750
(Kilometers) (126 000) (132 000) (138 000) (144 000) (150 000)
Change engine oil and engine oil filter. X² XL²X²XL²X²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XX
Inspect drive belt, replace as required. X
Change rear axle fluid. X
Change front axle fluid (4X4). X
Check transfer case fluid level (4X4). X
Inspect fan hub.X
Inspect damper.X
Inspect water pump weep hole for
blockage.X
Replace fuel filter element. Clean the water
in fuel sensor.X
Inspect front wheel bearings. X
Inspect brake linings.X
Inspect and adjust parking brake if
necessary.X
Drain and refill automatic transmission fluid.
Replace filter and adjust bands.X
DRLUBRICATION & MAINTENANCE 0 - 15
MAINTENANCE SCHEDULES (Continued)

Miles 97,500 100,000 101,250 105,000 108,750 112,500
(Kilometers) (156 000) (160 000) (162 000) (168 000) (174 000) (180 000)
Change engine oil and engine
oil filter.XL²X²XL²X² XL²
Lubricate outer tie rod ends
2500/3500 (4X4) models only.XXX
Flush and replace engine
coolant.X
Inspect drive belt, replace as
required.X
Inspect water pump weep
hole for blockage.X
Replace fuel filter element.
Clean the water in fuel sensor.X
Change rear axle fluid. X
Change front axle fluid (4X4). X
Inspect brake linings. X
Inspect and adjust parking
brake if necessary.X
Miles 116,250 120,000 123,750 127,500 131,250 135,000
(Kilometers) (186 000) (192 000) (198 000) (204 000) (210 000) (216 000)
Change engine oil and engine
oil filter.X² XL²X²XL²X² XL²
Lubricate outer tie rod ends
2500/3500 (4X4) models only.XXX
Clean engine air filter canister.X
Adjust valve lash clearance.X
Inspect drive belts, replace as
required.X
Drain and refill transfer case
fluid (4X4).X
Inspect fan hub. X
Inspect damper. X
Inspect water pump weep
hole for blockage.XX
Replace fuel filter element.
Clean the water in fuel sensor.XX
Inspect front wheel bearings. X
Change rear axle fluid. X X
Change front axle fluid (4X4). X X
Inspect brake linings. X X
Inspect and adjust parking
brake if necessary.XX
Drain and refill automatic
transmission fluid. Replace
filter and adjust bands.X
0 - 16 LUBRICATION & MAINTENANCEDR
MAINTENANCE SCHEDULES (Continued)

²LTier 1 EPA (250 hp or 305 hp) Engines Only
(see engine data label for your engine type)
²² California LEV (235 hp) Engines Only (see
engine data label for your engine type)Inspection and service should also be performed
anytime a malfunction is observed or suspected.
Schedule ªAº
Miles 7,500 15,000 22,500 30,000 37,500
(Kilometers) (12 000) (24 000) (36 000) (48 000) (60 000)
[Months] [6] [12] [18] [24] [30]
Change engine oil and engine oil filter. X² XL²X²XL²X²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XXXX X
Check transfer case fluid level (4X4). X
Inspect water pump weep hole for blockage X X
Replace fuel filter element. Clean the water
in fuel sensor.XX
Inspect drive belts, replace as necessary. X
Inspect brake linings. X
Inspect and adjust parking brake if
necessary.X
Inspect fan hub.X
Inspect damper.X
Inspect front wheel bearings. X
Miles 45,000 52,500 60,000 67,500 75,000
(Kilometers) (72 000) (84 000) (96 000) (108 000) (120 000)
[Months] [36] [42] [48] [54] [60]
Change engine oil and engine oil filter. XL²X²XL²X² XL²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XXXX X
Check transfer case fluid level. X
Flush and replace engine coolant at 60
months, regardless of mileage.X
Inspect drive belts, replace as necessary. X X
Inspect water pump weep hole for blockage X X X
Replace fuel filter element. Clean the water
in fuel sensor.XX
Inspect brake linings. X X
Inspect and adjust parking brake if
necessary.XX
Inspect fan hub. X
Inspect damper. X
Inspect front wheel bearings. X
Replace fuel filter element. Clean the water
in fuel sensorX
DRLUBRICATION & MAINTENANCE 0 - 17
MAINTENANCE SCHEDULES (Continued)

Miles 82,500 90,000 97,500 100,000 105,000
(Kilometers) (132 000) (144 000) (156 000) (160 000) (168 000)
[Months] [66] [72] [78] [84]
Change engine oil and engine oil filter. X² XL²X² XL²
Lubricate outer tie rod ends 2500/3500
(4X4) models only.XXXX X
Flush and replace engine coolant, if not
done at 60 mos.X
Check transfer case fluid level (4X4). X
Inspect drive belt, replace as required. X
Inspect fan hub. X
Inspect damper. X
Inspect water pump weep hole for
blockage.XX
Replace fuel filter element. Clean the water
in fuel sensor.XX
Inspect front wheel bearings. X
Inspect brake linings. X
Inspect and adjust parking brake if
necessary.X
Drain and refill automatic transmission fluid.
Replace filter and adjust bands.X
Miles 112,500 120,000 127,500 135,000 142,500 150,000
(Kilometers) (181 000) (193 000) (205 000) (217 000) (229 000) (241 000)
[Months] [90] [96] [102] [108] [114] [150]
Change engine oil and engine
oil filter.X² XL²X²XL²X² XL²
Lubricate outer tie rod ends
2500/3500 (4X4) models only.XXXXX X
Flush and replace engine
coolant, if it has been 160
000 km (100, 000 miles) or 60
months since last change.X
Inspect drive belt, replace as
required.XX
Drain and refill transfer case
fluid (4X4).X
Check tranfer case fluid level
(4X4).X
Inspect fan hub. X X
Inspect damper. X X
Inspect water pump weep
hole for blockage.XXX
Replace fuel filter element.
Clean the water in fuel
sensor.XXX
0 - 18 LUBRICATION & MAINTENANCEDR
MAINTENANCE SCHEDULES (Continued)

HYDRAULIC BOOSTER DIAGNOSIS CHART
CONDITION POSSIBLE CAUSES CORRECTION
Slow Brake Pedal Return 1. Excessive seal friction in booster. 1. Replace booster.
2. Faulty spool valve action. 2. Replace booster.
3. Restriction in booster return hose. 3. Replace hose.
4. Damaged input rod. 4. Replace booster.
Excessive Brake Pedal
Effort.1. Internal or external seal leakage. 1. Replace booster.
2. Faulty steering pump. 2. Replace pump.
Brakes Self Apply 1. Dump valve faulty. 1. Replace booster.
2. Contamination in hydraulic
system.2. Flush hydraulic system and replace
booster.
3. Restriction in booster return hose. 3. Replace hose.
Booster Chatter, Pedal
Vibration1. Slipping pump belt. 1. Replace power steering belt.
2. Low pump fluid level. 2. Fill pump and check for leaks.
Grabbing Brakes 1. Low pump flow. 1. Test and repair/replace pump.
2. Faulty spool valve action. 2. Replace booster.
STANDARD PROCEDURE - BLEEDING
The hydraulic booster is generally self-bleeding,
this procedure will normally bleed the air from the
booster. Normal driving and operation of the unit will
remove any remaining trapped air.
(1) Fill power steering pump reservoir.
(2) Disconnect fuel shutdown relay and crank the
engine for several seconds, Refer to Fuel System for
relay location and WARNING.
(3) Check fluid level and add if necessary.
(4) Connect fuel shutdown relay and start the
engine.
(5) Turn the steering wheel slowly from lock to
lock twice.
(6) Stop the engine and discharge the accumulator
by depressing the brake pedal 5 times.
(7) Start the engine and turn the steering wheel
slowly from lock to lock twice.
(8) Turn off the engine and check fluid level and
add if necessary.
NOTE: If fluid foaming occurs, wait for foam to dis-
sipate and repeat steps 7 and 8.
REMOVAL
NOTE: If the booster is being replaced because the
power steering fluid is contaminated, flush the
power steering system before replacing the booster.
(1) With engine off depress the brake pedal 5
times to discharge the accumulator.
(2) Remove brake lines from master cylinder.
(3) Remove mounting nuts from the master cylin-
der.
(4) Remove the bracket from the hydraulic booster
lines and master cylinder mounting studs.
(5) Remove the master cylinder.
(6) Remove the return hose and the two pressure
lines from the hydraulic booster (Fig. 55).
(7) Remove the booster push rod clip, washer and
rod remove from the brake pedal.
(8) Remove the mounting nuts from the hydraulic
booster and remove the booster.
DRBRAKES - BASE 5 - 31
HYDRO-BOOST BRAKE BOOSTER (Continued)

OPERATION
The heater warms the engine coolant providing
easier engine starting and faster warm-up in low
temperatures. Connecting the power cord to a
grounded 110-120 volt AC electrical outlet with a
grounded three wire extension cord provides the elec-
tricity needed to heat the element.
REMOVAL
(1) Disconnect the battery negative cables.
(2) Drain coolant from radiator and cylinder block
(Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(3) Unscrew the power cord retaining cap and dis-
connect cord from heater element.
(4) Using a suitable size socket, loosen and remove
the block heater element (Fig. 9).
INSTALLATION
(1) Clean and inspect the threads in the cylinder
block.
(2) Coat heater element threads with Mopart
Thread Sealer with Teflon.
(3) Screw block heater into cylinder block and
tighten to 55 N´m (41 ft. lbs.).
(4) Connect block heater cord and tighten retain-
ing cap.
(5) Fill cooling system with recommended coolant
(Refer to 7 - COOLING - STANDARD PROCE-
DURE).
(6) Start and warm the engine.
(7) Check block heater for leaks.
ENGINE COOLANT
TEMPERATURE SENSOR
DESCRIPTION
The Engine Coolant Temperature (ECT) sensor is
used to sense engine coolant temperature. The sensor
protrudes into an engine water jacket.
The ECT sensor is a two-wire Negative Thermal
Coefficient (NTC) sensor. Meaning, as engine coolant
temperature increases, resistance (voltage) in the
sensor decreases. As temperature decreases, resis-
tance (voltage) in the sensor increases.
OPERATION
At key-on, the Powertrain Control Module (PCM)
sends out a regulated 5 volt signal to the ECT sensor.
The PCM then monitors the signal as it passes
through the ECT sensor to the sensor ground (sensor
return).
When the engine is cold, the PCM will operate in
Open Loop cycle. It will demand slightly richer air-
fuel mixtures and higher idle speeds. This is done
until normal operating temperatures are reached.
The PCM uses inputs from the ECT sensor for the
following calculations:
²for engine coolant temperature gauge operation
through CCD or PCI (J1850) communications
²Injector pulse-width
²Spark-advance curves
²ASD relay shut-down times
²Idle Air Control (IAC) motor key-on steps
²Pulse-width prime-shot during cranking
²O2 sensor closed loop times
²Purge solenoid on/off times
²EGR solenoid on/off times (if equipped)
²Leak Detection Pump operation (if equipped)
²Radiator fan relay on/off times (if equipped)
²Target idle speed
Fig. 8 Engine Block Heater ± 5.9L Diesel Engine
1 - BLOCK HEATER
Fig. 9 Block Heater - 5.9L Diesel Engine
1 - BLOCK HEATER
7 - 38 ENGINEDR
ENGINE BLOCK HEATER - 5.9L DIESEL (Continued)