3116 Truck Engine Caterpillar

Caterpillar Diesel Engines can operate effectively in cold weather. The starting and the operation of the diesel engine is dependent on the following items in cold weather:

• The type of fuel that is used

• The viscosity of the oil

• Optional starting aids

• Optional warm up aids

The purpose of this section will cover the following information:

• Explain potential problems that are caused by cold weather operation.

• Suggest steps which can be taken in order to minimize starting problems and operating problems when the ambient air temperature is colder than 0 to −55 °C (32 to −67 °F).

The operation and maintenance of a machine in freezing temperatures is difficult to outline in a general publication. This is because of the following conditions: the unlimited differences in weather conditions, engine applications and the supplies that are available in your area. These factors, recommendations from your Caterpillar dealer, past proven practices, and the information that is contained in this section should be combined in order to provide guidelines for cold weather operations.

Hints for Cold Weather Operation

• If the engine is started, operate the engine until a minimum operating temperature of 71 °C (160 °F) is achieved. Achieving operating temperature will help prevent the intake valves and exhaust valves from sticking.

• The cooling system and the lubrication system for the engine do not lose heat immediately upon shutdown. This means that an engine can be shut down for a few hours and the engine can still have the ability to start readily. If the engine is shut down for at least eight hours, the engine should be considered cooled to outside temperature.

• Install the correct lubricant in each compartment before the beginning of cold weather.

• Check all rubber parts (hoses, fan drive belts, etc) weekly.

• Check all electrical wiring and connections for any fraying or damaged insulation.

• Keep all batteries fully charged and warm.

• Fill the fuel tank at the end of each shift.

• Check the air cleaners and the air intake daily. Check the air intake more often when you operate in snow.

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Personal injury or property damage can result from alcohol or starting fluids. Alcohol or starting fluids are highly flammable and toxic and if improperly stored could result in injury or property damage.

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DO NOT USE ETHER (starting fluids) unless specifically instructed to do so. If the engine is equipped with an Air Inlet Heater (electrically or fuel ignited manifold heater), DO NOT use ether (starting fluids) at any time. The use could result in engine damage and/or personal injury.

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NOTICE
The optional automatic ether injection system is the only starting fluid system that is recommended. Excessive starting fluid can cause piston and ring damage. Use starting fluid for cold starting purposes only.

• Inject starting fluid only when the engine is cranking.

• Dryers for the air system may be effective in reducing moisture condensation and the formation of ice in air systems.

• Alcohol injection may prevent moisture from freezing the air compressor governor and other components of the air system.

• For jump starting with cables in cold weather, refer to the Operation and Maintenance Manual for jump starting instructions.

Viscosity of the Engine Lubrication Oil

Proper engine oil viscosity is essential. Oil viscosity affects the amount of torque that is needed to crank the engine. Refer to the Operation and Maintenance Manual, "Lubricant Specifications" for the recommended viscosity of oil.

Lubricating Oil Heaters

Note: Oil pan immersion heaters are not recommended for heating the lube oil. To ensure the compatibility of the components, only use equipment that is recommended by Caterpillar.

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NOTICE
Heating elements that are in direct contact with the lubricating oil can cause coking of the oil. To aviod coking of the oil when the oil is heated, follow these recommendations: The temperature of the heating surface must not exceed 150 °C (300 °F). The maximum heat density of the heating surface must not exceed 1.24 w/cm2 (8W/in2).

Engine oil pan heaters are useful devices that provide the following functions:

• Assist in reducing the cranking amperage that is needed to start the engine.

• Improve the flow of oil at start-up.

• The time that is needed to warm up the engine is reduced.

• The service life of bearings is increased.

Engine oil pan heaters can reduce the minimum ambient temperatures that are normally recommended for multigrade API CG-4 oil. Consult your truck dealer for more information.

Recommendations for the Coolant

Provide cooling system protection for the lowest expected outside temperature. Refer to the Operation and Maintenance Manual, "Lubricant Specifications" for the recommended coolant mixture.

In cold weather, check the coolant often for the proper glycol concentration in order to ensure adequate freeze protection.

Jacket Water Heater

A jacket water heater heats the coolant that surrounds the combustion chamber. This provides the following functions:

• Startability is improved.

• Warm up time is reduced.

• The required temperature for ether is reduced.

An electric jacket water heater can be activated once the engine is stopped. An effective jacket water heater is typically a 1250/1500 W unit. Consult your truck dealer for more information.

Idling the Engine

When idling after the engine is started in cold weather, increase the engine rpm to 1000 to 1200 rpm. This will warm up the engine more quickly. The engine should not be “raced” in order to speed up the warm up process.

While the engine is idling, the application of a light load (parasitic load) will assist in maintaining the minimum operating temperature. The minimum operating temperature is 71 °C (160 °F). Maintaining an elevated low idle speed for extended periods will be easier with the installation of a hand throttle. An idle speed of 1000 rpm is preferred for all engines.

Exhaust Restrictor

A load is applied to the engine by the exhaust restrictor in order to reduce the warm up time and white smoke at engine start-up. When extended idling periods are unavoidable, the exhaust restrictor can help maintain acceptable coolant temperatures above 71 °C (160 °F). Exhaust restrictors for the engines can also be obtained from other companies.

Recommendations for Coolant Warm Up

Warm up any system that has cooled below normal operating temperatures due to inactivity. This should be performed before the engine is returned to full operation. During operation in very cold temperature conditions, damage to engine valve mechanisms can result from engine operation for short intervals. This can happen if the engine is started and the engine is stopped many times without being operated in order to warm up completely.

When the engine is operated below normal operating temperatures, fuel and oil are not completely burned in the combustion chamber. This fuel and oil causes soft carbon deposits to form on the valve stems. Generally, the deposits do not cause problems and the deposits are burned off during operation at normal engine operating temperatures.

When the engine is started and the engine is stopped many times without being operated in order to warm up completely, the carbon deposits become thicker. This will cause the following problems:

• Free operation of the valves is prevented.

• Valves become stuck.

• Push rods are bent.

• Other damage to valve train components can result.

For this reason, when the engine is started, the engine must be operated until the coolant temperature is 71 °C (160 °F) minimum. Carbon deposits on the valve stems will be kept at a minimum and the free operation of the valves and the valve components will be maintained.

In addition, the engine must be thoroughly warmed in order to keep other engine parts in better condition and the service life of the engine will be generally extended. Lubrication will be improved. There will be less acid and less sludge in the oil. This will provide longer service life for the engine bearings, the piston rings, and other parts. However, limit unnecessary idle time to ten minutes. Engine wear is greatest at low idle and unnecessary idling wastes fuel.

On/Off Fan Clutch

Viscous fans continuously rotate in cold weather, which creates unnecessary movement of the air. For better control of the operation of the fan, an ON/OFF fan clutch may be used. ON/OFF fan clutches can help prevent excessive cooling in cold weather. In the "OFF" position, the fan is kept stationary by the ON/OFF fan clutch. The unnecessary movement of the air is reduced in order to maintain adequate engine operating temperatures in cold weather.

Purge Valve and Insulated Heater Lines

During periods of operations with a light load, The coolant must bypass the radiator in order to help prevent excessive cooling of the engine. Coolant that passes through the radiator must be minimized in order to maintain the engine operating temperature in cold weather.

Excessive cooling of the engine is prevented by a “jiggle” valve that performs two functions. The valve allows the flow of air and the valve prevents the flow of coolant. These valves prevent the unnecessary coolant flow, which may be diverted around the water temperature regulator to the radiator.

Insulated cab heater lines for very cold weather are also beneficial. These lines provide more available heat from the coolant to the cab and less heat is lost to the outside air.

Air Inlet and Cab Insulation

When temperatures below −18 °C (−0 °F) will be frequently encountered, an air cleaner inlet that is under the hood may be specified. This is sometimes referred to as a “Snow Valve”. An air cleaner that is under the hood may also minimize the snow that is packed in the air cleaner. Heat that is rejected by the engine warms the inlet air.

Additional heat can be retained around the engine by specifying additional insulation for the cab and for the hood when the vehicle is ordered. This will improve the comfort level of the operator.

Winter Front or Shutters

With the introduction of air-to-air aftercooling, the use of winter fronts or shutters for normal operation above freezing requires caution in order to avoid high inlet temperatures and high exhaust temperatures. The restriction in air flow can cause the following problems:

• higher exhaust temperatures

• power loss

• excessive fan usage

• reduction in fuel economy

Winter fronts or shutters are useful in maintaining minimum engine coolant temperatures when the outside air temperatures drop below freezing. Regardless of the ambient temperature, if the engine coolant temperature is above the minimum of 71 °C (160 °F), a winter front is not required. When a winter front is used, the coolant temperature should be monitored with the dash gauge so the engine does not overheat.

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NOTICE
Failure to open the winter fronts with the engine under load could cause engine damage and/or loss of fuel economy

Apply The following guidelines when winter fronts or shutters are used.

• If the ambient temperature is higher than 1 °C (34 °F), then open or remove the winter front.

• If the ambient temperature is between −18 to 0 °C (−0 to 32 °F), then use a winter front with an opening directly in line with the fan hub. The shape of the opening should be a circle or a diamond. The opening should be a minimum of 385 cm ² (60 in ² ).

• If the ambient temperature is between −29 to −18 °C (−20 to −0 °F), then use a winter front with an opening of 192.5 cm ² (30 in ² ).

• If the ambient temperature is between −34 to −29 °C (−30 to −20 °F), then use a winter front with an opening of 102 cm ² (16 in ² ). Position the opening directly in line with the fan hub.

• If the ambient temperature is below −34 °C (−30 °F), then close the winter front.

• Close the winter front If you idle the engine overnight.

Generally, winter fronts are less expensive than radiator shutters. If radiator shutters are installed, then the thermostat for the shutter should open the shutters at a preset temperature. The preset temperature should be 6 °C (10 °F) lower than the opening temperature of the engine thermostat.

Charts for Cold Weather Operations (Recommendations)

The following charts were designed to assist dealers and customers in order to equip the Caterpillar Diesel Engine effectively for cold weather operation. You should select starting aids that allow the engine to start at the various temperature ranges without the need for extended cranking periods. If extended idling periods are unavoidable, you should consider the use of the idle temperature and coolant warm up devices. These devices are based on the maximum expected temperatures. The objective is maintaining a minimum engine coolant temperature of 71 °C (160 °F).

Table 1

Recommendations for Cold Weather Operations Caterpillar Medium Duty Truck Engines
Starting Aid
Coldest Temp. Expected	Ether Aid(1)	Block Heater	Larger ALT or Battery	Air Inlet Heater(1)
Above −7 °C (20 °F)	Available	Available	Available	Standard
−7 to −18 °C (20 to 0 °F)	Available	Available	Available	Standard
−18 to −28 °C (0 to −20 °F)	Recom'd	Required	Recom'd	Standard
−28 to −40 °C (−20 to −40 °F)	Recom'd	Required	Required	Standard
Below −40 °C (−40 °F)(2)	Required	Required	Required	Standard

(1)	Use ONLY the automatic ether injection system if the engine is equipped with an air inlet heater.
(2)	Consult the OEM of the vehicle.

Table 2

Recommendations for Cold Weather Operations Caterpillar Medium Duty Truck Engines
Assistance for Idle Temperature and Coolant Warm Up
Coldest Temp. Expected	(Mech ENG) Hand Throttle	Winter Front or Shutter (1)	Snow Valve (2)	On/Off Fan Drive (3)	Exhaust Restrictor (4)
Above −7 °C (20 °F)	Available	Available	Available	Available	Available
−7 to −18 °C (20 to 0 °F)	Available	Recom'd	Recom'd	Recom'd	Available
−18 to −28 °C (−0 to −20 °F)	Recom'd	Required	Recom'd	Recom'd	Recom'd
−28 to −40 °C (−20 to −40 °F)	Required	Required	Recom'd	Required	Recom'd
Below −40 °C (−40 °F) (5)	Required	Required	Recom'd	Required	Required

(1)	Refer to the topic, "Winter Front or Shutters" in this manual.
(2)	The snow valve allows inlet air to be drawn from under the hood.
(3)	Or low speed viscous fan clutch. Required below −40 °C (−40 °F).
(4)	Not available from the factory. Consult your Caterpillar dealer.
(5)	Consult the OEM of the equipment.

Table 3

Recommendations for Cold Weather Operations Caterpillar Medium Duty Truck Engines for Bus Applications
Assistance for Idle Temperature and Coolant Warm Up
Coldest Temp. Expected	(Mech ENG) Hand Throttle	Winter Front or Shutter (1)	Snow Valve (2)	On/Off Fan Drive (3)	Exhaust Restrictor (4)
Above −7 °C (20 °F)	Available	Available	Available	Available	Available
−7 to −18 °C (20 to 0 °F)	Available	Recom'd	Recom'd	Recom'd	Available
−18 to −28 °C (−0 to −20 °F)	Recom'd	Required	Recom'd	Recom'd	Recom'd
−28 to −40 °C (−20 to −40 °F)	Required	Required	Recom'd	Required	Recom'd
Below −40 °C (−40 °F) (5)	Required	Required	Recom'd	Required	Required

(1)	Refer to the topic, "Winter Front or Shutters" in this manual.
(2)	The snow valve allows inlet air to be drawn from under the hood.
(3)	Or low speed viscous fan clutch. Required below −40 °C (−40 °F).
(4)	Not available from the factory. Consult your Caterpillar dealer.
(5)	Consult the OEM of the equipment.