TIMING BELT AND WATER PUMP : MX5 HOW TO

Introduction

This tutorial provides step-by-step instructions for replacing the timing belt and water pump on an MX5. This essential maintenance task can help prevent engine damage and ensure your vehicle runs smoothly. Follow these steps carefully for a successful replacement.

Chapter 1: Preparing the Vehicle

• Jack Up the Car:

  • Use a jack to lift the vehicle securely.
  • Ensure the car is on a flat surface and use jack stands for safety.

• Drain the Cooling System:

  • Safety First: Ensure the coolant is cool to avoid burns.
  • Remove Under Tray:
    • Unscrew three bolts at the front and two at the back.
    • Remove two bolts from each wheel arch.
  • Remove Radiator Cap: This relieves pressure before draining.
  • Drain Coolant:
    • You can use the drain bung, but it's safer to remove the lower coolant pipe to minimize mess.

Chapter 2: Removing Components

• Remove Air Intake System:

  • Disconnect the intake at the specified points (crank breather, air temperature sensor, mass airflow).

• Remove the Radiator (optional but recommended):

  • Disconnect the top radiator hose from the thermostat filler neck.
  • Disconnect overflow pipe and radiator fan wires.
  • Remove support brackets and lift the radiator out.
  • Detach water lines from the thermostat housing.

• Remove Auxiliary Belt:

  • Loosen the three bolts on the water pump pulley without removing them completely.

• Remove Harmonic Balancer:

  • Use a socket to hold the 21mm bolt while unscrewing the four 10mm bolts.
  • Pull the harmonic balancer off carefully.

Chapter 3: Accessing the Timing Belt

• Remove Coil Packs and Valve Cover:

  • Refer to spark plug and valve cover replacement videos for detailed instructions.

• Remove Timing Belt Covers:

  • Upper cover: Remove four bolts.
  • Lower cover: Remove three bolts (one near the water pump).

• Remove Crank Bolt:

  • This bolt may be very tight; use a breaker bar, ensuring the car is in gear with the handbrake on. If necessary, remove the anti-roll bar to gain access.

Chapter 4: Timing Belt Removal

• Prepare for Belt Removal:

  • Ensure the engine is at top dead center (TDC) by aligning marks on the crank and cam pulleys.

• Lock Camshafts:

  • Use a cam locking tool for precise timing or adjustable wrenches with mole grips.

• Remove Timing Belt:

  • Loosen the tensioner pulley bolt and remove the tensioner spring.
  • Remove the tensioner and idler pulley, allowing the belt to fall off.

Chapter 5: Water Pump Replacement

• Remove Old Water Pump:

  • Unbolt and detach the water pump from the engine.
  • Ensure mating surfaces are clean for the new pump.

• Install New Water Pump:

  • Apply sealant on the new gasket and install the pump.
  • Torque the bolts to 22Nm in a cross pattern and reattach the water neck bolts at 20Nm.

Chapter 6: Installing New Timing Belt

• Install New Components:

  • Replace the woodruff key on the crankshaft.
  • Install the new idler pulley and torque to 50Nm.
  • Install the new tensioner pulley and spring.

• Install Timing Belt:

  • Start by placing the belt on the crank pulley.
  • Route the belt around the idler and exhaust cam.
  • Use tie wraps to secure the belt during installation on the intake cam.

• Tension the Belt:

  • Release the tensioner and ensure the belt tension is appropriate by measuring deflection (9-11.5mm).

Chapter 7: Reassembly and Final Checks

• Reassemble Components:

  • Follow the reverse order of removal for all components.

• Fill the Cooling System:

  • Use a 50/50 mix of deionized water and coolant.
  • Pour slowly to avoid trapping air.

• Start the Engine:

  • Ensure the heater is set to hot to circulate coolant.
  • Run the engine and check for leaks.
  • Allow it to reach operating temperature, then turn off and top off the coolant.

Conclusion

Replacing the timing belt and water pump in an MX5 requires careful attention to detail and following each step closely. Make sure to follow torque specifications and check all connections before starting the engine. With proper execution, this maintenance task can significantly prolong the life of your engine. If you found this guide helpful, consider subscribing for more automotive tutorials.