XJ6 Series 1 Cooling System

[ronniegraywk486]

What is the correct type of anti-freeze for this 4.2 engine
Ronnie Gray

[mike020150]

Good old-fashioned 'Bluecol' or equivalent is the correct antifreeze. If you are unsure what's been used previously, ensure you flush the system thoroughly before adding the new antifreeze. Mixing old and modern antifreeze materials can cause problems by causing precipitation which blocks water passages and results in overheating. Mike.