FOREWORD

Operating a diesel engine during cold weather requires prop-

erly controlling the engine's operating environment. Because

most engines operate in climates that are neither ideal nor

Theconstant they must be modified to perform satisfactorily.

electrical, fuel, lubricating, intake air, and cooling systems~

are affected by cold temperatures and each system requires

modifications that vary with the severity of the weather

program provides solutions to cold weather operatingThis

problems that are proven effective in minimizing engine dam-

age and improving reliability and performance. Cold weather

operating aids, good maintenance practices and operating

procedures provide better starting, faster warm-up, better

Providing proper coldfuel economy and less down -time .

weather protection for the engine saves operating costs for

the engine owner

Produced by:T. W. TedderDistribution Training

Copyright@ 1983Cummins Engine Company, I nc.

(Title Slide)1.

The purpose of this training program isto stress the requirement for modifyingCummins diesel engines for operation incold climates. Controlling the engine'soperating environment will prevent thesevere problems that result from improp-er protection and assu re satisfactoryengine performance.

2.

3. Most diesel engines are subject to coldweather operating problems. However ,Cummins has proven solutions thatinclude preparing the equipment, alongwith improved maintenance and opera-tional practices that will result inminimized engine damage and improvedreliability. These solutions are onlyeffective if you are aware of the"not-so-obvious" problems and take theappropriate action to provide the properoperating environment for the engine.

The materials used in the construction ofa diesel engine and the liquid systemsthat keep it operating are definitelyaffected by cold weather. Metal, oil,fuel, coolant, and batteries are all poten-tial problem areas. ,

4.

5 When the weather is cold fuel waxing hasa major effect on fuel flow. Lines andfilters may become restricted, shuttingoff the fuel supply. Extremely low tem-peratures also cause batteries to storeenergy at a lower rate and require ahigher charging rate. Batteries willfreeze if allowed to discharge. Theseconditions make starting the engine verydifficult.

6. Fuel consumption is also affected bychanges in the temperature. Increasedair density and the higher winds experi-enced during the winter months result inoverall higher ai r resistances. Coldtires generate higher rolling resistance.Parasitic losses in the engine and drivetrain are higher due to reduced lubricanttemperatures.

7 I n most equipment the cooling system isdesigned to provide adequate enginecooling up to the maximum ambient tem-peratures in which the equipment will beused. When this equipment is used inextremely cold conditions, the systemhas more capacity than required andchanges must be made or special equip-ment installed to avoid cold-operatingengines.

8 Equipment that is normally operated in awarm climate, but periodically is movedinto a colder climate, is the most vulner-able. This equipment must be preparedfor the coldest expected operating condi-tions, as well as the operatingtemperature where the equipment isbased.

9. Cold air can be detrimental to a dieselengine, particularly when it is com-pressed by turbocharging. As the tem-perature decreases, air densityincreases. In a turbocharged engine,the higher density can cause so muchincrease in cylinder pressure that. ..

10 head gaskets can blow and cylinder headcapscrews may break. Piston burning orcracked pistons and piston ring beat-incan also occur. Other possible problemsinclude excessive bearing loads and dam-age to, or premature failures of, thecylinder heads and block.

";f

11 Another area of cold weather problems ismetal temperatures. Various metals areaffected differently by low temperatures,some contracting more than others. Theclearances between mating parts canincrease, and parts that were properlysecured may even work loose. When theparts affected contain fluids such as oilor coolant, leaks develop.

12. Keeping diesel fuel flowing is one of therecu rring problems of winter. Becauseit will "cloud and wax" , diesel fuel canliterally clog up its own lines and filter-ing system. Like the air system, thefuel system can experience cold weatherproblems while the engine is operating .It is a common experience for the engineto stop during operation due to awax-clogged filter.

7. Batteries are a source of energy used tocrank the engine. As the battery tem-perature decreases, so does the bat-tery's ability to supply power. At thesame time, the engine's cran king loadincreases, requiring more power to turnthe engine.

18 Engine manufacturers normally recom-mend battery and electrical systemcapacities for specific engine families toprovide adequate starting at 00 F (-18°C). Operation in colder ambientsrequ i res additional batteries, or the bat-teries must be heated to allow them toregain their electrical capacity.

19. Several methods may be employed to heatthe battery. If fuel-fired engine com-partment, cab or coolant heaters areused, the hot air or coolant can be asource of heat for the battery. Batteryheaters that require a source of electricpower may be used. Insulated batteryenclosu res must be vented and automaticthermostat controls must be providedwith the electric heaters to preventoverheating the battery.

.

20 Failing to provide adequate batterycapacity will result in low crankingspeed. However, proper cable size,length and connections are key factors inproviding the transfer of power from thebattery to the cran king motor. Under-sized cables restrict the flow of electricalenergy, while loose or corroded cablesand connections can reduce the availablebattery power by 5096 or more before itreaches the cranking motor.

5

21. To prevent damaging the crankingmotor, do not crank a diesel engine formore than 30 seconds at a time (as speci-fied in the Operation/MaintenanceManual) .If the engine does not startafter three attempts, investigate the rea-son.

22. Heavy-duty cranking motors aredesigned to withstand longer crankingperiods at higher amperage withoutoverheating. They are most efficientwhen the engine is cranked at 100 to 150rpm. When a cold engine is cranked atreduced cran king speeds, efficiencydrops and current flow increases. If thecranking motor stalls during enginecranking, 100% of the electrical energyturns to heat. The result is aburned-up cranking motor and wiring.

23 When air cranking motors are used,exercise caution regarding the size oftubing, fittings, and the types of valvesused. The system must be free of airleaks. A clean moisture-free air supplymust be provided and the unit must bewell lubricated.

24 The fuel system requires special atten-tion du ring cold weather. This systemprovides storage of fuel on the vehicleand the delivery of fuel from the tan ksto the combustion chambers th rough fuellines, water separators, fuel filters, thefuel pump and the injectors. The freeflow of fuel through this system dependson its temperature and the pour pointand cloud point of the fuel used .

6

25 Diesel fuel "clouding or waxing" isbecoming more of a problem each yearbecause of the decreasing availability ofNo.1 fuel for blending. Pour pointdepressants may reduce the size of waxcrystals in the fuel, but they do notalter the temperature at which thesecrystals form. The best method forpreventing wax formation in diesel fuel isto maintain the temperature of the fuelabove the cloud point.

26 Blending No.1-0 with No.2-0 dieselfuel will reduce the wax and cloud pointof the blended fuel. However, afterblending, the lubricating quality andBTU content of the fuel is also reducedwhen comparing it to No.2-0 diesel fuel.

(1

27 Under no circumstances should gasoline,gasohol or alcohol be blended with dieselfuel. This practice creates an extremefire hazard and, under certain cicum-stances, an explosive hazard. Use ofthese fuels may also damage the fuel sys-tem components, due to lack oflubrication .

:,

28 Moisture is troublesome in diesel fuel atall times of the year, but particularly incold weather. In fact, ice crystals willform in diesel fuel. Condensation andwater most often begins in bulk storagetanks. For this reason, these tanksshould be tested often with a waterdetecting material, and drained orpurged if necessary.

29. Condensation in the vehicle fuel tankoccurs when air in the tank cools duringthe shut-down period. This can bereduced by topping-off the fuel tanksbefore shut-down to reduce the volumeof the air space above the fuel.

30 Water and ice can clog the standard fuelfilter provided on the engine. Keepingthe fuel tanks full and draining the con-densate daily when the engine is warmwill belp reduce the moisture. However,any moisture remaining in the fuel mustbe removed to ensure dependable engineperformance. A fuel filter/water separa-tor installed on the suction side of thefuel pump in place of the existing fuelfilter will provide filtering and removemoisture from the fuel.

ttr'

31 Adding a commercial fuel warmer and/ora fuel filter/water separator in serieswith existing filters may increase therestriction at the fuel inlet. Wheninstalling these options, make certainyou don't exceed the fuel inletrestriction limit listed on the data sheet.Note: Typical maximum fuel inletrestriction is four (4) inches of mercury(100mm Hg) with a new fuel filter.

32 The purpose of a fuel warmer is to pre-vent fuel filter plugging due to wax. Todo this it must be capable of supplyingenough heat to the fuel at its maximumflow rate to raise the fuel from the lowestexpected ambient temperature, and main-tain a temperature above the fuel's cloudpoint.

33. The thermo blend fuel warmer useswarmed fuel from the injector fuel returnline to heat the cold fuel in the fuel sup-ply line. A thermal valve preventsoverheating as the thermo-blend warmerrecycles the hot return fuel through thefuel system .

~

34. Another type of fuel warmer uses enginecoolant as a source of heat. Coolantheating during shut-down allows thewarmer to become effective very quicklyafter the engine starts. To prevent fueloverheating, an opitional thermostat isavailable that automatically by-passesfuel flow around the warmer when thefuel temperature is above the cloud orwax point. If thermostats are not avail-able, a means of shutting off coolant flowth rough the heater must be provided .

,

35. A fuel warmer will not help if the fuel isbelow the pour point and cannot bepumped to the warmer. During coldweather conditions, fuel should beblended with a light distillate fuel ortreated with a pour point depressant tolower the pour point.

36 The next consideration in the startingand performance of a diesel engine du r-ing cold weather is the Lubricating Sys-tem. The two physical properties of thelube oil that are vital to the lubricationof the engine during cold start-ups arepour point and viscosity. The oilselected must be able to flow throughthe engine under any extremeconditions .~

37. Although it may be possible to start anengine if the oil is too viscous to flow,doing so would result in catastrophicengine failures due to lack oflubrication .

~

38. Using a low- or multi-viscosity oil willimprove:.engine starting and warm-up.power out-put of the engine.the engine's fuel consumption.wear during engine starting.Use the highest vicosity oil that providessatisfactory starting and engine opera-tion.

39 If the oil being used does not have theproper pour point or viscosity, it is nec-essary to heat the engine lube oil beforestarting the engine. Electrically pow-ered oil immersion type heaters may beused to decrease the oil viscosity andreduce friction during cranking. Wherefuel-fired coolant heaters are used,enclosing the engine compartment andinsulating the oil pan will retain heatfrom the coolant flow through the block.

\

40. The arctic lube oil requirements shownhere are for engines operating in areaswhere the ambient temperature is con-sistently below -25° F (-32° C), andwhere there is no inside storage or pro-vision for keeping the engine warmduring shut-down. Oils meeting theserequi rements usually have synthetic-basestocks.

41. Because cold weather operation putsadditional stress on diesel engines, youmust follow some special oil-related main-tenance practices. First, it is partic-ularly important to observe the enginemanufactu rer's recommended oil changeintervals.

42. Also, due to the contraction of metals atlow temperatures, check the engine fre-quently for both coolant and oil leakage.When operatin9 at a temperature below-100 F (-23° C), check the oil level aftereach workshift. The lubricating oilshould also be checked frequently forcoolant and fuel contamination .

""'

r.43. Next we'll review the air intake system

and the precautions that should betaken. As we mentioned, ai r temper-ature affects air density.

,

44. Earlier in the program, we mentioned theeffect that an increase in air density canhave on a turbocharged diesel engine.This chart illustrates the rise in peakcylinder pressu re as the ambient temper-ature becomes extremely cold and the airdensity rises.

45. Cold intake air will cause irregular com-bustion, resulting in high wear rates anddamage in the combustion chamber. Dueto the low intake temperature, the enginecompression may not produce enoughheat to ignite the fuel and air mixture.

46. Intake air generally needs to be warmedwhen the temperature reaches 32° F (00C). However, depending on enginedesign, the ambient temperature at whichan engine will support combustion canvary by 30 or 40 degrees. You shouldprovide a means of warming the intakeair or creating heat in the intake mani-fold to support combustion and helpreduce white smoke.

47. An aftercooler in the intake manifold isthe best method of warming the intakeair. The aftercooler element, used tocool heated air from the turbochargercompressor when the engine is at operat-ing temperatu re, will also warm coldintake air to near the temperature of thecoolant.

48. When the ambient temperature is below32° F (00 C) , pulling the intake air fromwithin the engine compartment will nor-mally provide sufficient preheating forcomplete combustion. Sealing the enginecompartment and providing a temperaturecontrolled on-off type fan will preventthe dissipation of heat from air flow with-in the engine compartment.

49. Obtaining intake air from within theengine compartment can be accomplishedby mounting the air cleaner inside thecompartment. Routing intake pipingfrom the engine compartment to the aircleaner is another satisfactory method ofobtaining warm air from the engine com-partment.

50. When a higher level of heat is required,the engine exhaust pipe may be used toheat the intake air. Regardless of thetype of arrangement used to provideheated intake air, provisions must bemade to provide air from outside theengine compartment or away from theexhaust pipe when operating at higherambient temperatures.

51. The use of preheated intake air from anaftercooler or the engine compartmentwill normally support combustion, pro-vided that a coolant or engine compart-ment heater and a fuel heater are beingused.

,

52. However, diesel engines that are exposedto the elements in ambient temperaturesin the 30 to 50° F (-1 to 10° C) rangemay require a starting aid, such asether, which will permit ignition at alower temperature. Using ether will low-er the ambient temperature at whichignition will occu r by about 50° F (25°C) .I n warmer climates it may be theonly starting aid needed .

53. Complete starting aid kits may beinstalled that consist.of a pressure cyl-inder of ether dispensed by a meteringvalve. Atomizers that administer a mea-sured starting fluid charge are recom-mended to properly control the flow ofether into the intake manifold.

54. Spraying ether di rectly into the ai rcleaner is not a recommended practice.If ether is sprayed directly into the aircleaner intake, the air cleaner, after-cooler and all piping must be filled withether before any ether reaches theintake ports. An uncontrollable, exces-sive volume of volatile fluid vapor canresult, which may continue to burn dur-ing compression, exhaust, and intakeportions of the firing cycle. This cancause extreme damage to the engine.

55 Do not use ether starting aids in con-junction with a flame-type manifold pre-heater starting aid. An explosion mayoccur in the intake system that can dam-age the engine or cause personal injury.Also never use ether starting aids whilethe engine is operating. Uncontrolledhigh cylinder pressu res will seriouslydamage the engine.

56 Serious damage can also occur to theengine and engine components if thecooling system isn't properly preparedfor cold weather operation. The coolantwithin the system is primarily a heattransfer medium and is subject to freez-ing in cold and arctic climates.

57. Antifreeze helps to keep the coolant in aliquid state, but there's a limit to it'seffectiveness. The maximum recom-mended is a mixture of 68% antifreeze and32% water. This mixture will turn slushyat about -600 F (-50° C) .When fillingthe cooling system or topping off theradiator, use a properly-premixed sol-ution that is suitable for the lowesttemperature expected. This will assu rethat the desired antifreeze/water ratio ismaintained.

58 I n cl imates where the temperatu re isbetween 30 and 50° F (-1 to 10° C) , it isnecessary to either heat the coolant oruse a s.tarting aid to successfully startthe engine. And in climates where it iscolder than -10° F (-23° C), Cumminsrecommends that coolant heaters be usedin conjunction with a starting aid .

59. A coolant heater must heat the volume ofcoolant contained in the cylinder blockand the accessories in the coolantby-pass system. For maximumefficiency, the heater should maintainthe coolant temperature at a minimum of1200 F (50° C) in any ambient temper-ature encountered.

~

60 The immersion type coolant heaters haveheating elements inserted in the coolantpassage in the cylinder block where themaximum amount of coolant can surroundthe heater. Heat is transferred to thecylinder block and liners via the heatedcoolant. Due to the space limitationswithin the coolant passages, the immer-sion type heater wattage is limited to2500 watts or less. An external sourceof electrical power must be provided tooperate these heaters. Heaters must bedisconnected when the engine is operat-ing.

61. Tank type coolant heaters that functionon the convection principal may also beused. These externally mounted heaterswarm coolant within the tank and circu-late it through the cylinder block andcoolant by-pass system. This methodworks similar to the way a percolator cof-fee pot forces water up through the stemwhen brewing. Accessory pumps areavailable to provide improved circulation .

62. Tank type coolant heaters require anexternal electrical power source. Theremote mount tank type has one impor-tant advantage over an immersion type.An optional thermostat can be installedso that electrical power can be saved .Ideal for stationary engines, these 1000to 4000 watt heaters also have an optionaloil pressure cut-off switch which is nec-essary for generator sets.

63. Fuel-burning coolant heaters are avail-able for equipment at remote locationswhere electrical power is notavailable.These heaters are designed toburn liquid/vapor fuels. Some will oper-ate on a mixture of fuels; however, themost commonly-used heaters burn dieselfuel, propane or gasoline.

64. The fuel-burning heater is a furnace guntype heater where the fuel is ignited andthen sprayed into a transfer mediumsuch as a porous ceramic disc. Thisflame heats the coolant via coils in theheater. Convection or a recirculatingpump in the heater transfers theheated coolant through the engine.Fuel-burning heaters have a higher heat-ing capacity than the electrical typeheaters.

16

65. Both electrical and fuel-burning tanktype coolant heaters are versatile intheir application. 'n addition to heatingengine coolant, properly-sized heaterscan be used for heating the engine com-partment, cab, fuel lines, batteries,torque converters and other accessories.

66. During engine operation, heat within theengine compartment can be controlledwith a temperature controlled fan drive.These fan drives function by completelyor partially disconnecting the fan fromits drive source at a specified temper-ature.

67. The flow of cold air across the radiatorcore into the engine compartment canbe prevented by installing radiator shut-ters. Because air flow has a major effecton heat loss through radiation, reducingthe air flow with shutters will reduce thetime required for engine warm-up andhelp maintain engine operating temper-ature.

~

68. Canvas or plastic "winter front" andengine compartment covers may berequired when operating in cold temper-atures. "Winter front" and engine com-partment covers will protect the engineand engjne compartment from cold airflow and eliminate shutter leakage."Winter fronts" are designed so that thecover opening must be adjustedmanually, depending on the ambient tem-perature and operation of the radiatorshutters. Engine compartment coversmust not restrict the air intake andexhaust systems during operation .

69 I nsulating the engine or engine compart-ment will not prevent moisture in the airfrom passing through the air compressorand forming ice in the air brake systemor air starter. To prevent a malfunctionor complete failure, install a method ofintroducing alcohol into the air system onall vehicles equipped with air brakes andair starters that operate where the tem-perature is below 32° F (00 C).

70 Air dryers that provide an in-Iine filtra-tion system are also available. The fil-tration system removes both liquid andwater vapor from the compressor dis-charge air before it reaches theair-brake reservoirs and air starter.This results in a clean, dry air supplythroughout the system, aiding in theprevention of air line freeze-ups.

7 Cummins recommends that the engine beoperated at an idle no-load condition forNO MORE than fifteen minutes at anyonetime. Operating the engine at idle speedin cold ambient temperatures wastes fuel,accelerates wear, and can result in seri-ous engine damage such as stuck valvesand burned pistons.

72 If prolonged engine idling is required,the engine must be idled at an rpm, orwith a load, that is adequate to maintainthe coolant temperature above 14OD F(GOD C) .For this type operation, a fullon-off type fan and winter front must beused. I n addition, the thermostat,thermostat seal and deaerating systemmust not allow coolant leakage throughthe radiator core with the thermostat inthe closed position .

18

Following prolonged full-load operation,the engine should be run at idle speedfor several minutes prior to shut-down .This allows time for the cooling system toproperly stabilize the engine and compo-nents at a lower operating temperature.

73

tI

74. It is possible to operate diesel engines inextremely cold environments if they areproperly equipped. As the operatingtemperature DECREASES, the number ofrequired cold weather operating aidsI NCREASES .Modifications such asunder-hood air, engine enclosures, etc.,are required for satisfactory operationand long engine life.

75 When winterizing equipment, the th reebasic objectives that must be accom-plished are: 1) Reasonable startingcharacteristics followed by practical anddependable warm-up of the engine, 2)An installation that is as independent aspossible from external sources, and 3)Modifications to equipment that will main-tain sati$factory engine operatingtemperatures with a minimum increase inmaintenance and costs.

76. The cold weather starting and operatingaids discussed in this program aredesigned to extend the useful range ofthe equipment. Successful operation is,however, dependent upon a high stand-ard of maintenance, both in preparingfor and operating equipment in low ambi-ent temperatures where severe operatingconditions are imposed .

77. We offer publications that include " Air

for Your Engine", "Engine Operation inCold Weather" , and the recommendedspecifications for lubricating oil, dieselfuel, batteries and battery cables. "ThePrinciples of Troubleshooting" and"Troubleshooting Cooling Systems forCold Engine Operating Temperatures"are also included. The publications areavailable from your Cummins Distributor.

78. It is possible to operate du ring coldambient temperatu res with very littledetrimental effect on the engine. How-ever, it is the responsibility of theengine owner to see that the engine isproperly protected. Cummins EngineCompany, Inc. makes every effort toassure that engine owners and operatorsare aware of cold weather operation

requirements.

20

COLD WEATHER OPERATION QUIZ

TRUE FALSE

All of the operating systems of a dieselengine are affected by cold weather.

1

2. The cooling system, designed to operateefficiently in high ambient temperatures,has more cooling capacity than required forcold weather operation .

3 If a battery fails to provide adequateenergy for starting when operating intemperatures below OaF the battery mustbe replaced.

Clouding or waxing of diesel fuel can beprevented when operating at a temperaturebelow the fuel's cloud point.

4

5 Cooling heated air from the turbochargercompressor, du ring operation, is the onlyfunction of an aftercooler.

Ether starting aid kits are required only whenoperating in temperatures below 30°F (-1°C) .

6.

A coolant heater may be required even thoughan ether starting aid is being used .

7

8 Controlling the air flow across the radiatorcore can reduce the time required for enginewarm-up and help maintain the engine operatingtemperature.

9. Cummins recommends that the engine notbe operated at an idle no-load condition for aprolonged period of time.

~;

I nstalling cold weather starting aids willguarantee a successful operation.

10