1978/01/18 Caterpillar


Valve Damage Can Be Caused By Short Intervals Of Engine Operation In Very Cold Temperatures

Usage:


All Engines

According to field reports, some customers have had problems with damage to engine valve components during operation in very cold temperature conditions. These problems are the result of engine operation for short intervals, where the engine is started and stopped many times but does not run long enough to become completely warm.

During the interval of time that the engine operates at temperatures below normal, fuel and oil are not completely burned in the combustion chambers. This fuel and oil causes soft carbon deposits on the valve stems. Generally, these deposits do not cause problems because they are burned off during operation at normal engine temperatures. When the engine is started and stopped at short intervals, and the engine temperature is never up to normal, the carbon deposits become thicker until they prevent free operation of the valves. This can cause burnt valves, bent push rods, or other damage to valve components.

For this reason, any time the engine is started, the recommendation is to run the engine until the coolant temperature is 150°F (66°C) or higher. This will keep carbon deposits on the valve stems at a minimum.

In addition, operation of the engine until it is thoroughly warm will keep the other engine parts in better condition and generally extend the service life of the engine. Lubrication will be improved, with less acid and sludge in the oil. This will give longer service life for engine bearings, piston rings, and other parts.

Caterpillar Information System:

1978/01/18 List Of Service Publications
1978/01/18 Improved Seal Used Between Impeller And Bearings On Water Pump Shaft
1978/01/18 Improved Water Pump Group Now Used
1978/01/18 New Turbine Housings Are The Replacement For Three Former Turbine Housings Used On Schwitzer Turbochargers
1978/01/18 Improved Water Shield For Exhaust Manifold
1978/01/18 Improved Front Pulley And Damper Groups Use New Damper Adapter With Larger Diameter Bolt Circle For Pulley Bolts
1978/01/18 Maintenance Instructions For Coolant Conditioner Elements
1977/12/14 Add Chamfer To Cartridge Assembly Bearings To Prevent Oil Leakage
1977/12/14 Excessive Oil Consumption Can Be Caused By Dirt In Air Inlet System Or By Flaking Of The Piston Compression Ring
1977/12/14 Water Separators Needed On Engines In The Field With SMFS
1977/12/14 List Of Service Publications
1977/12/14 New Coolant Tube And Regulator Housing Used With Water Cooled Exhaust Manifold Gives More Clearance For Hooks To Lift The Engine
1978/01/18 Inner Member Of Caterpillar Coupling Must Be Restrained If The Connection To The Inner Member Is Removed
1978/01/18 Tolerance Added To Valve Clearance Specifications
1978/01/18 Turbine Housing For Turbocharger Is Stronger
1978/01/18 5P8665 Cylinder Liner Puller Makes Liner Removal Easier And Faster
1978/01/18 Improved Gasket Prevents Oil Leakage From The Governor
1978/02/08 Change In Design Of Engine Governor, Fuel Injection And Transfer Pump Groups, And Fuel Ratio Control Groups
1978/02/08 Do Not Change Factory Fuel Or Speed Settings On Truck Engines Unless New Settings Are Certified Under Applicable EPA Regulations
1978/02/08 Attachment Groups Put Corrosion Inhibitor Directly Into Cooling System
1978/02/08 Complete Set Of Contact Points For Dial Indicators Is Now Available In One Group
1978/02/08 New Water Temperature Regulator Opens At 180 °F (82°C){1350,1355,7304}
1978/02/08 Probable Causes Of Low Fuel Delivery During Testing On Fuel Injection Test Benches
1978/02/08 Oil Strainer (Screen) Added To Turbocharger Thrust Bearing
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