1. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems AURT202166A Repair cooling systems AUR30405 CERTIFICATE III IN AUTOMOTIVE MECHANICAL TECHNOLOGY

2. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Types of cooling systems All internal combustion vehicles have a cooling system. 2

3. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Why have a cooling system? Remove excess heat so the engine temperature doesn’t go too high. Maintain a minimum engine operating temperature. Give a rapid engine warm up. 3

4. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Heat Transfer Heat can be transferred in three ways: 1.Conduction- heat transfers through the metal parts 2.Convection- heat transfers through the coolant 3.Radiation- heat transfers from the metal parts to the outside air. 4

5. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems 5 Cooling system operation Extremely high temperatures are created inside the engine. The heat is transferred into the coolant. The coolant is pumped through the radiator core and fins. Air passing through the radiator fins reduces the coolant temperature.

6. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Cooling system construction 6 Expansion bottle Hose Radiator cap Temp sender Heater tap Cabin heater core Cylinder Head gasket Welsh plug Heater hose Drain plug Automatic transmission cooler line Fan belt Hose Fan

7. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Engine coolant safety Coolant is a mixture of water and chemicals and it is poisonous. Wear personal protective equipment. Store or recycle used coolant safely. Don’t pour down drains. 7

8. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Radiator cap safety 1.Allow the engine to cool down. 2.Place a thick rag over the cap. 3.Turn the cap anti-clockwise – 1/4 of a turn. 4.Press down cap and remove. 8

9. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems External leaks External coolant leaks can be in: coolant hoses radiator welsh plugs radiator cap. 9 Use a pressure tester to find external cooling system leaks. Always check operating instructions before use.

10. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Internal leaks Internal coolant leaks can be in: cylinder head gasket cracked cylinder head cracked cylinder block. 10 For an accurate diagnosis use a CO 2 leak detector to help identify internal cooling system faults. Always consult CO 2 leak detector operating instructions before use. Head gasket leaking coolant

11. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Cooling system checklist Complete the inspection checklist to ensure: you identify all cooling system faults you make accurate recommendations and quotes. 11

12. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Reverse Flushing What is reverse flushing? 12 Forcing water through the cooling system in the opposite direction to clean the cooling system. Why do we reverse flush? To remove rust and scale from the cooling system To remove the old coolant to avoid cross contamination. Water out Water in

13. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Welsh plugs Designed to seal the casting holes. Made from mild steel or brass. Most vehicles use the cup welsh plug. Can leak coolant if cooling system is neglected. 13

14. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Water pump Pumps the coolant through the engine and radiator. Repair or replace when: noisy leaking coolant causing engine to overheat. 14

15. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Thermostat A temperature sensitive control valve. Ensures engine reaches operating temperature quickly. Controls the operating temperature of the cooling system. 15

16. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Thermostat testing Test the thermostat to check: opening temperature correct operation. 16

17. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Cooling fans Test for: Correct operation Noisy fan motor Damaged fan blades. 17

18. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Radiator and hoses May need removing to: Repair radiator leaks or blockages Replace the water pump Replace engine or components Service cooling hoses. 18

19. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems Radiator and hoses 19

20. AURT202166A REPAIR COOLING SYSTEMS © Commonwealth of Australia 2011 AURT202166A Repair Cooling Systems 20 © Commonwealth of Australia 2011 ISBN: 978-1-876838-58-4 This document is available under a “Free for Education” licence for educational purposes – see http://www.aesharenet.com.au/FfE2 for details.http://www.aesharenet.com.au/FfE2 This work is copyright. You may download, display, print and reproduce this material in whole or in part or in modified form (retaining this notice) for your personal, non-commercial use or use within your organisation. If you use, display, or reproduce this material or a modified form of it in whole or in part within your organisation you must include the following words in a prominent location within the material in font not less than size 12: ‘The views expressed in this publication do not necessarily represent the view of the Minister for Education or the Australian Government. The Australian Government does not give any warranty nor accept any liability in relation to the contents of this work’. Apart from any use as permitted under the Copyright Act 1968, all other rights are reserved. Requests and inquiries concerning reproduction and rights should be addressed to the Commonwealth Copyright Administration, Attorney General’s Department, Robert Garran Offices, National Circuit, Barton ACT 2600 or posted at http://www.ag.gov.au/cca. Funded under the Workplace English Language and Literacy (WELL) Program by the Australian Government Department of Education, Employment and Workplace Relations. The views expressed in this publication do not necessarily represent the view of the Minister for Education or the Australian Government. The Australian Government does not give any warranty nor accept any liability in relation to the contents of this work.