Possible Causes & Corrections

Check the following items:

• Check coolant level. Check cooling system thermostat for proper operation and application.
• Check for restricted airflow to radiator or restricted coolant flow through radiator.
• Check for loose water pump belt.
• Check Engine Coolant Temperature (ECT) sensor, Reading should be within 5°F of ambient air temperature on a cold engine.
• Check fuel injection pump and timing. See appropriate ON-VEHICLE ADJUSTMENTS article.
• Check injector nozzles. See appropriate SYSTEM & COMPONENT TESTING article.
• Inspect fuel delivery system. Check for no fuel to injection pump or air in fuel system. See BASIC FUEL SYSTEM CHECKS (DIESEL) in appropriate BASIC DIAGNOSTIC PROCEDURES article.
• Check for incorrect basic engine parts such as camshaft, cylinder heads and pistons.
• Check for excessive blow-by.