Mazda Mazda6 Repair Manual 2003-2011

• 2.3L DOHC 16-valve VTT inline 4 (engine code L3)
• 2.5L DOHC 16-valve VVT inline 4 (engine code L5)
• 3.0L DOHC 24-valve VVT V6 (engine code AJ)
• 3.7L DOHC 24-valve VVT V6 (engine code MZI)

INTAKE MANIFOLD | REMOVAL AND INSTALLATION

UPPER INTAKE MANIFOLD

WARNING: If you are going to be removing the lower intake manifold, relieve the fuel system pressure before proceeding (see Chapter 4).

REMOVAL (Refer to illustrations 5.5 and 5.12)

1. Disconnect the cable from the negative battery terminal (see Chapter 5).



2. Remove the air filter housing and the intake duct (see Chapter 4).



3. Remove the engine cover, if equipped.



4. Disconnect the connector at the electronic throttle body, and any coolant hoses or other connectors at the throttle body.



5. On 3.0L engines, disconnect the MAP sensor connector, the EGR valve electrical connector and the EGR pipe (see illustration).



6. Disconnect the EVAP hose, brake booster vacuum hose and PCV hose.



7. On 3.7L engines, disconnect the heated PCV valve connector.



8. Disconnect the vacuum lines and electrical connectors from the upper intake manifold. Be sure to mark them with tape to insure correct reassembly.



9. Remove the wire harness bracket nuts and position the wiring harness off to the side. On 3.7L engines, remove the manifold brace, near the throttle body end of the manifold.



10. Remove the mounting bolt from the upper manifold brace(s). On some models, there is both a long brace and a short brace (near the throttle body).



11. Loosen the upper intake manifold bolts. Follow the opposite of the tightening sequence (see illustration 5.15a or 15.b). Note: The bolts are captive and come out with the manifold.

BRAKE HOSES AND LINES | INSPECTION AND REPLACEMENT

1. About every six months, with the vehicle raised and placed securely on jackstands, the flexible hoses which connect the steel brake lines with the front and rear brake assemblies should be inspected for cracks, chafing of the outer cover, leaks, blisters and other damage.
   
   These are important and vulnerable parts of the brake system and inspection should be complete. A light and mirror will be needed for a thorough check. If a hose exhibits any of the above defects, replace it with a new one.


FLEXIBLE HOSES (Refer to illustrations 8.3a and 8.3b)


2. Clean all dirt away from the ends of the hose.



3. To remove a brake hose, unscrew the tube nut with a flare-nut wrench, if available, to prevent rounding-off the corners of the nut, then remove the bolt(s) or clip(s) securing the hose to the body (and any suspension components)(see illustrations).



4. Disconnect the hose from the caliper, discarding the sealing washers on either side of the fitting.



5. Using new sealing washers, attach the new brake hose to the caliper. Tighten the banjo fitting bolt to the torque listed in this Chapter's Specifications.



6. Reverse the removal procedure to install the hose, making sure it isn't twisted.



7. Carefully check to make sure the suspension or steering components don't make contact with the hose. Have an assistant push down on the vehicle and also turn the steering wheel lock-to-lock during inspection.



8. Bleed the brake system (see Section 9).


METAL BRAKE LINES


9. When replacing brake lines, be sure to use the correct parts. Don't use copper tubing for any brake system components. Purchase steel brake lines from a dealer parts department or auto parts store.



10. Prefabricated brake line, with the tube ends already flared and fittings installed, is available at auto parts stores and dealer parts departments. These lines can be bent to the proper shapes using a tubing bender.

• Tune-up and routine maintenance
• General engine overhaul procedures
• Cooling, heating and air-conditioning systems
• Fuel and exhaust systems
• Engine electrical systems
• Emissions control systems
• Transmission
• Driveline
• Brakes, ABS
• Suspension and steering systems
• Body
• Chassis electrical system
• Wiring diagrams