2021 RAM 2500 Owners Manual - NORMAL OPERATION — DIESEL ENGINE

NORMAL OPERATION — DIESEL ENGINE

Observe the following when the engine is operating:

All message center lights are off.

Malfunction Indicator Light (MIL) is off.

Engine oil pressure is above 10 psi (69 kPa) at idle.

Voltmeter operation:

The voltmeter may show a gauge fluctuation at various engine temperatures. This cycling operation is caused by the post-heat cycle of the intake manifold heater system. The number of cycles and the length of the cycling operation is controlled by the engine control module.

Post-heat operation can run for several minutes, and then the electrical system and voltmeter needle will stabilize.

The cycling action will cause temporary dimming of the headlamps, interior lamps, and also a noticeable reduction in blower motor speed.

COLD WEATHER PRECAUTIONS

Operation in ambient temperature below 32°F (0°C) may require special considerations. The following charts suggest these options:

Use “Ultra Low Sulfur Diesel Fuels” ONLY.

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*Number 1 Ultra Low Sulfur Diesel Fuel should only be used where extended arctic conditions (0°F/-18°C) exist”.

Use of Climatized Ultra Low Sulfur Diesel Fuel or Number 1 Ultra Low Sulfur Diesel Fuel results in a noticeable decrease in fuel economy.

Climatized Ultra Low Sulfur Diesel Fuel is a blend of Number 2 Ultra Low Sulfur and Number 1 Ultra Low Sulfur Diesel Fuels which reduces the temperature at which wax crystals form in fuel.

The fuel grade should be clearly marked on the pump at the fuel station.

The engine requires the use of “Ultra Low Sulfur Diesel Fuel”. Use of incorrect fuel could result in engine and exhaust system damage page 477.

If Climatized or Diesel Number 1 ULSD fuel is not available, and you are operating below (20°F/-6°C), in sustained arctic conditions, Mopar® Premium Diesel Fuel Treatment (or equivalent) is recommended to avoid gelling (see Fuel Operating Range Chart).

Under some circumstances increased engine noise may be audible in the seconds following a cold start. This is most likely to

occur when using fuel that isn't blended for the ambient temperature present. This may occur on an unseasonably cold day or when a truck is fueled in a warmer climate and driven to a colder climate. The noise can typically be prevented by using Mopar® Premium Diesel Fuel Treatment as recommended (see Fuel Operating Range Chart).

For the correct engine oil viscosity page 408.

A Winter front or cold weather cover is to be used in ambient temperatures below 32°F (0°C), especially during extended idle conditions. This cover is equipped with four flaps for managing total grille opening in varying ambient temperatures. If a Winter front or cold weather cover is to be used the flaps should be left in the full open position to allow air flow to the charge air cooler and automatic transmission oil cooler. When ambient temperatures drop below 0°F (-17°C) the four flaps need to be closed. A suitable cold weather cover is available from your Mopar® dealer.

A battery loses 60% of its cranking power as the battery temperature decreases to 0°F (-18°C). For the same decrease in temperature, the engine requires twice as much power to crank at the same RPM. The use of 120 VAC powered battery blankets will greatly increase starting capability at low temperatures. Suitable battery blankets are available from an authorized dealer.

Avoid full throttle operation when the engine is cold. When starting a cold engine, bring the engine up to operating speed slowly to allow the oil pressure to stabilize as the engine warms up.

High-speed, no-load running of a cold engine can result in excessive white smoke and poor engine performance. No-load engine speeds should be kept under 1,000 RPM during the warm-up period, especially in cold ambient temperature conditions.

Your vehicle is equipped with an engine warm-up protection feature that may limit engine performance after cold starting at low ambient temperatures. The length of time engine speed is limited is dependent upon

engine coolant temperature. Engine speed may be briefly limited to 1000 RPM after starting with coolant temperature below freezing conditions, and may be limited to 1000 RPM for up to approximately two minutes under more severe cold conditions.

If ambient temperatures are low and the coolant temperature is below 180°F (82°C), the engine idle speed will slowly increase to 1,000 RPM after two minutes of idle, if the following conditions are met:

Foot is off brake pedal and throttle pedal.

Automatic transmission is in PARK.

Vehicle speed is 0 mph (0 km/h).

Applying the throttle will cancel fast idle.

Operating the exhaust brake at idle will greatly improve warm-up rate and will help keep the engine close to operating tempera- ture during extended idle.

ENGINE IDLING

Avoid prolonged idling, long periods of idling may be harmful to your engine because combustion chamber temperatures can drop so low that the fuel may not burn completely.

Incomplete combustion allows carbon and varnish to form on piston rings, engine valves, and injector nozzles. Also, the unburned fuel can enter the crankcase, diluting the oil and causing rapid wear to the engine.

If the engine is allowed to idle or the truck is driven on low engine speed drive cycles for more than two hours, the system will automatically enter an emissions operating mode that will increase the engine idle speed to 900 RPM. While in this mode, which is designed to help maintain the diesel particulate filter, the engine idle speed will return to normal when the brake pedal is applied. A small change in engine tone or a slight change in engine performance while accelerating may also be noticeable at speeds below 20 mph (32 km/h). This operating mode may last for up to an hour of idle time, or around 20 minutes of driving time.

Your truck may have been ordered with an optional voltage monitoring idle-up feature. If a load is placed on the electrical system while the

truck is in park, this feature will attempt to maintain normal system voltage by automatically increasing engine idle speed. You may notice several consecutive increases in idle speed, up to a maximum of 1,450 RPM, as the system will attempt to utilize the smallest increase in idle speed necessary to maintain normal system voltage. The idle speed will return to normal when either the electrical load

is removed, or when the brake pedal is applied. 4

For instrument cluster display messages related to the vehicle's exhaust system page 111.

The driver-controlled high idle speed feature will help increase cylinder temperatures and provide additional cab heat, however, excessive idling may still cause the exhaust aftertreatment system to not properly regenerate. Extended periods of idle time should be avoided.

The Idle-Up feature uses the Cruise Control buttons to increase engine idle speed and quickly warm the vehicle's interior.

With the transmission in PARK, the parking brake applied, and the engine running, push the On/Off button to the ON position, then push the SET (-) button.

The engine RPM will go up to 1,100 RPM. To increase the RPM, push and hold the RES (+) button and the idle speed will increase to approximately 1,500 RPM. To decrease the RPM, push and hold the SET (-) button and the idle speed will decrease to approxi- mately 1,100 RPM.

To cancel the Idle–Up feature, either push the CANCEL button, push the On/Off button, or press the brake pedal.

NOISE

Diesel engines can create noises that may seem concerning. The nature of a diesel engine is compression ignition where compressed air

and fuel are mixed and ignited. Weather, barometric pressure, altitude, and temperature will affect how fuel is ignited in the engine.

Engines will sound different from day to day or previous model years. Clicking, ticking, or light knocking is normal and will change from day to day, as the engine breaks in, and can vary with changes in ambient temperature. Clicking sound from under the hood shortly after vehicle shutdown is normal as actuators such as the EGR valve are cycled. Fuel pump noise may increase during low speed/light load conditions when ambient temperature is above 100°F (38°C), and when fuel tank level is below 10% which is a normal condition of the fuel system and controls strategy. Diesel equipped vehicles also have an exhaust after-treatment system to reduce emissions utilizing a Diesel Particulate Filter (DPF) and a Selective Reduction Catalyst (SCR). The SCR reduces Nitrogen Oxides (NOx) using the Diesel Exhaust Fluid (DEF) system.

DEF is injected directly into the SCR through a dosing module. This process will create a clicking sound and at times, will make noise even with the vehicle shut off. This is normal as the DEF dosing module is purging DEF. If at any time the check engine light is on, please visit an authorized dealer.

STOPPING THE ENGINE

Idle the engine a few minutes before routine shutdown. After full load operation, idle the engine three to five minutes before shutting it down. This idle period will allow the lubricating oil and coolant to carry excess heat away from the combustion chamber, bearings, internal components, and turbocharger. This is especially important for turbocharged, charge air-cooled engines. Refer to the following chart for proper engine shutdown:

IDLE SHUTDOWN

This feature can be enabled so that the truck will automatically shutdown when the truck has been idling for a set period of time when the engine is at operating temperature. Idle time can be set in 5 minute increments between

5 and 60 minutes. See an authorized dealer to enable this feature.

The idle shutdown timer is disabled while the PTO is active.

PROGRAMMABLE MAXIMUM VEHICLE SPEED

This feature allows the owner to set a maximum vehicle speed for the vehicle. The 2500 and 3500 Series maximum vehicle speed can be set between 40 mph (64 km/h) and 87 mph

(140 km/h). The 4500/5500 Series maximum

vehicle speed can be set between 40 mph (64 km/h) and 85 mph (136 km/h). See an authorized dealer to enable this feature.

DO NOT set the maximum vehicle speed to a value greater than what the vehicle tires are rated for.

OPERATING PRECAUTIONS

The temperature of the engine coolant (antifreeze) (a mixture of 50% ethylene-glycol and 50% water) must not exceed the normal range of the temperature gauge 240°F (116°C) with a 21 psi (145 kPa) coolant pressure cap.

Usually the engine coolant (antifreeze) temperature indicated during operation will be

to the left of center in the normal range of the 4

gauge.

Continual operation at low engine coolant (antifreeze) temperature below the normal range on the gauge 140°F (60°C) can be harmful to the engine. Low engine coolant (antifreeze) temperature can cause incomplete combustion which allows carbon and varnish to form on piston rings and injector nozzles. Also, the unburned fuel can enter the crankcase, diluting the lubricating oil and causing rapid wear to the engine.

COOLING SYSTEM TIPS

To reduce potential for engine and transmission overheating in high ambient temperature conditions, take the following actions:

City Driving — When stopped, shift the trans- mission into NEUTRAL and increase engine idle speed.

Highway Driving — Reduce your speed.

Up Steep Hills — Select a lower transmission gear.

Air Conditioning — Turn it off temporarily.

When the engine is at normal operating temperature, the minimum oil pressures required are:

All engine failures give some warning before the parts fail. Be on the alert for changes in performance, sounds, and visual evidence that the engine requires service. Some important clues are:

Engine misfiring or vibrating severely.

Sudden loss of power.

Unusual engine noises.

Fuel, oil or coolant leaks.

Sudden change, outside the normal oper- ating range, in the engine operating tempera- ture.

Excessive smoke.

Oil pressure drop.