YOKE ASSEM. 7G2506 - Caterpillar

If a problem with the cooling system is suspected, inspect the cooling system before you perform any tests on the cooling system.
Check the coolant level in the cooling system. Refer to Operation and Maintenance Manual, "Cooling System Coolant Level - Check".
Make sure that the coolant meets the recommendations of the Operation and Maintenance Manual. Also, make sure that the coolant has the following properties:
Color that is similar to new coolant
Odor that is similar to new coolant
Free of dirt and debris
Look for leaks in the cooling system. After the engine is stopped, look for coolant or steam from the radiator's overflow. Inspect the hoses and clamps for good condition. If engine oil or coolant is leaking from the joint between the cylinder head and the engine block, there is a problem with the cylinder head gasket.Note: The water pump has a weep hole between the seal for the coolant and the seal for the bearing. The weep hole prevents coolant from entering the lubrication system if there is a problem with a seal in the water pump. A small amount of coolant at the weep hole is normal.
Make sure that air flows through the radiator and that there is not a restriction. Look for radiator fins that are bent, damaged, or leaking. Look for dirt and debris that can restrict the flow of air through the fins.
Inspect the fan drive belts and pulley grooves. A loose fan drive belt wears at a faster rate than a belt with the proper tension. A loose belt can damage the pulleys. A loose belt can slip. Substances such as oil and grease will cause the belts to slip.
Check for damage to the fan blades. Look for damaged baffles on the radiator and for baffles that are missing. Inspect the shroud of the fan for good condition.
Inspect the air inlet system. Make sure that the air cleaner, the air inlet, and the exhaust are not restricted.
Look for signs of air or combustion gas in the coolant. Air and/or gas in the coolant results in foaming of the coolant.
Pressurized System: Hot coolant can cause serious burns. To open the cooling system filler cap, stop the engine and wait until the cooling system components are cool. Loosen the cooling system pressure cap slowly in order to relieve the pressure.
After the engine is cool, remove the cooling system filler cap slowly in order to release pressure. Inspect the filler cap. Check the condition of the gasket. Check the sealing surface for the cap. The gasket and the sealing surface must be clean and free of gouges, nicks, and grooves.