Lesson 5/Learning Event 2
Learning Event 2:
DESCRIBE MAINTENANCE AND TROUBLESHOOTING PROCEDURES OF LIQUID-COOLING
SYSTEMS
The inspection procedures for the cooling system are about the same for all vehicles. But repair procedures
vary a great deal. You should always refer to the technical manual for the vehicle you are working on for
specific procedures and specifications. When you are working on the cooling system of a vehicle, you will
probably inspect the complete system before making any repairs. But in this lesson, let's discuss the inspection,
repair, and replacement of parts, one part at a time, to prevent confusion and repetition.
Radiator
Examine the radiator for proper coolant level, leaks, blocked air passages, secure mounting, and plugged
overflow. White, rusty, or colored stained spots indicate a leak. If plain water is used as the coolant, these
spots may not be damp as water evaporates quickly when it is hot. If an ethylene glycol antifreeze is used,
small leaks are more likely to be damp as this type of antifreeze does not evaporate. The radiator should be
replaced if any leaks are found.
When coolant is lost from the cooling system, refill it to check for leaks. But if the engine is overheated, do
not just pour in cold water right away. Allow the engine to cool, or refill the radiator slowly while the engine
is running. If cold water is poured into the radiator when the engine is overheated, there is danger of cracking
the cylinder block or head.
Remove any leaves, bugs, or other foreign matter in the radiator core or brush guard where it can reduce the
amount of cooling air flowing through the core. Foreign matter that is stuck between the radiator cooling fins
can be cleaned out with water and compressed air. However, you should not use any water for this until you
have checked the complete cooling system for leaks.
Check the radiator mounting for loose or missing bolts. Also check the radiator for being loose where the
tanks are soldered to the mounting frame. Tighten or replace any loose or missing bolts. If the radiator-to-
mounting-frame soldered joints are loose, the radiator should be replaced or it may be repaired at a higher
maintenance level.
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