Chapter 48 PowerPoint

Define these Technical Terms using the textbook:

1. belt tension gauge

2. coolant voltage test

3. cooling system pressure test

4. freeze plug

5. overcooling

6. overheating

7. radiator cap

8. refractometer

9. thermostat housing

Answer these discussion questions using the textbook:

1. What is a combustion leak test?

Read the chapter summary below:

■ Cooling systems remove heat produced by engine combustion and electrically-generated heat.

■ To troubleshoot a cooling system, gather information from the vehicle owner, review on-board diagnostic trouble codes, reference cooling system diagnosis charts, and perform a visual inspection of the system.

■ Coolant system problems typically involve, coolant leaks, overheating, or overcooling.

■ Over cooling may be indicated by slow engine warm-up, insufficient warmth from the heater, low fuel economy, sluggish engine performance, or a low reading from the coolant temperature sensor.

■ A bad water pump may leak coolant, fail to circulate coolant, or produce a grinding sound.

■ A stuck thermostat can cause either engine overheating or engine overcooling.

■ Air trapped in the cooling system can cause engine overheating or damage to the parts near the air pocket and hot spot.

■ Hardened cooling system hoses become very brittle and crack from engine vibration.

■ A softened cooling system hose is weakened and will usually swell, which can result in a rupture and leak.

■ Radiator shops have the facilities to properly disassemble, clean, solder, adhesive bond, reassemble or repair, and pressure test any radiator.

■ A loose belt will slip and squeal, and may rotate the water pump and fan too slowly.

■ A faulty engine fan can cause overheating, over-cooling, vibration, and water pump damage.

■ Visual inspection and basic tests will help determine the coolant level and condition.

■ A 50/50 mix of antifreeze and water is commonly used to provide protection for most weather conditions.

■ Flushing (cleaning) of a cooling system should be done when rust or scale is found in the system.

■ A defective temperature gauge may read hot or cold when the engine is actually at its proper operating temperature.

■ Supercharger cooling systems often operate at much lower pressures and temperatures than engine cooling systems.

■ Hybrid cooling systems may use liquid cooling, air cooling, or both, and are serviced similarly to an engine cooling system.