PROBLEMS
Problems Not Requiring Disassembly of the Cooling System
1. Remove large obstructions (equipment not approved by GM) blocking the radiator or condenser.
• Auxiliary oil cooler(s).
• License plates.
• Spare tires.
• Ice, mud, or snow obstructing the grille.
• Fog lamps.
2. Engine oil is overfilled.
3. incorrect radiator for the application.
• Check the part number.
4. Loose, damaged, or missing air seals.
5. Missing or damaged lower air baffle.
6. Incorrect ignition timing.
Problems Requiring Disassembly of the Cooling System
1. Incorrect or damaged fan.
2 . Worn or damaged emission system components.
• Could cause overheating at idle.
• Damaged positive crankcase ventilation (PCV) valve, thermal vacuum valve (TVV), or engine coolant temperature switch (ECT).
3. Radiator filler neck damage.
• Shows if the pressure cap leaks because of radiator filler neck damage.
4. Worn or damaged coolant pump.
• Impeller vanes eroded or broken.
• Worn or damaged bearing and/or seal. Check for shaft or bearing play.
5. Plugged radiator tubes.
• Perform a flow check.
6. Internal system leaks.
• Head gasket.
• Cracked block.
• Timing chain cover.
• Intake manifold gasket.
7. Plugged coolant passages in the cylinder heads.
• Visual check.
