DIESEL ENGINES don't like going out in the cold. They really don't like starting in cold weather.
To aid fleet operators in keeping engines operating efficiently in winter, Navistar International offers some advice on operating practices.
As the temperature drops, diesels are harder to start, because air temperature does not become as hot during compression, a real drawback when compression provides the only heat source for fuel ignition. International says fleets should make use of all available starting aids such as glow plugs, block heaters, oil heaters, and ether kits.
Glow Plugs in Small Engines Some small engines come equipped with glow plugs. These small electrical resistance coils heat the air in engine cylinders enough to allow compression to produce the proper ignition temperature. Most engines with glow plugs will start easily and instantly at temperatures down to -20 degrees F.
Block heaters also are helpful, especially at temperatures below -20 degrees. Block heaters should be activated as soon as engines are shut down to prevent rapid cylinder block cooling.
Larger engines, International's in-line six-cylinders for example, are not equipped with glow plugs. Starting these engines in extremely cold conditions can be made easier with the use of ether kits that inject a specific amount of ether into the intake manifold. Under no circumstances should ether be used in engines equipped with glow plugs, International says.
For starting in environments below -20 degrees F, International recommends oil pan heaters. These devices provide two benefits. First, they raise engine temperature and aid starting. Second, by heating the oil, they ensure that oil can flow through the engine properly for lubrication.
Allow for Warm-Up Diesel engine coolant should be allowed to reach at least 160 degrees F before a load is applied to the engine. International offers a Cold Ambient Protection feature that increases idle rpm to speed engine warm-up. This feature is standard on International medium duty engines. A hand throttle also can be used to control engine speed for more rapid warm-up.
Not only must diesel engines be warmed-up before operation, but drivers must guard against extended idling and rapid cool-down. Allowing an engine to idle in cold weather can be harmful, because this could result in a drop in coolant temperature below 160 degrees F where incomplete fuel combustion can result in excessive carbon deposits on valve stems and valve guides. Shutting off an engine without a short cool-down period also can be harmful.
Idling an engine to keep the cab heated may be necessary, but it is not necessary to ensure starting if the engine was at the proper temperature when shut down. Large engines actually cool more slowly when shut down than when running at low idle rpm. Unless weather is extremely frigid, a well-maintained engine will start readily if it has not been shut down for an extended period. Obviously, idling consumes fuel and raises operating costs.
Engine fans with an on/off switch can be helpful in cold weather. Turning the fan off will allow the engine to remain at its optimum operating temperature. Viscous fans can run too much in cold weather, removing excess heat from the engine through the cooling system.
Winter Checklist International says that fleet operators should follow a seven-step checklist for winter operation. Following the checklist will prevent damage to the engine and help minimize maintenance problems. The steps are
* Check all rubber parts such as hoses and belts on a weekly basis;
* Keep batteries fully charged;
* Check electrical wiring for frayed or damaged insulation and connectors for corrosion on a regular basis;
* Keep fuel tanks as full as possible to prevent condensation on the inside of exposed tank walls;
* Fill the fuel tank anytime the engine will be shut down for more than eight hours;
* Check the engine air inlet and air filters daily, especially when operating in snowy conditions; and
* Use an appropriate grade of fuel-diesel 1-D or winterized 2-D in temperatures below -20 degrees F.