Note: A new O-ring will be required during installation.
Note: The following procedure only applies to models with a Bosch fuel pump and without air conditioning.
Removal
1. The thermostat is located on the left end of the cylinder head (see illustration).
9.1. Thermal actuator on the left end of the cylinder head.
2. Partially drain the fluid from the cooling system.
3. Loosen the screw or nut and remove the end from the cable on the fast idle lever on the fuel pump (see illustration).
9.3. Fast idle speed control cable tip.
4. Pull the cable housing off the bracket on the fuel pump.
5. Unscrew the thermostat actuator from the cylinder head and remove the actuator together with the cable. Remove the O-ring (see illustration).
9.5. Unscrew the thermal actuator from the cylinder head. Note the O-ring seal (marked with an arrow).
Installation
6. Install the actuator in place using a new O-ring and tighten it.
7. Fill the cooling system.
8. Insert the cable housing into the bracket on the fuel pump.
9. Insert the cable into the fast idle lever and place the end on the cable, do not tighten the screw or nut yet.
10. Adjust the cable as described in the following steps.
Checking and adjusting
Note: During this procedure, the engine speed must be measured. A conventional tachometer, which operates from ignition system pulses, cannot be used on diesel engines. For this purpose, there is a diagnostic coupling to which Renault diagnostic equipment is connected, but it is usually not available to the car owner. If you cannot adjust the idle speed by ear or using the tachometer on the dashboard, you can use the following recommendations.
- Buy or borrow an appropriate tachometer.
- Leave the work to a Renault dealer or other specialist.
- Use the comparative method. The strobe light is controlled by a gasoline engine running at the desired speed. If a stroboscope is aimed at a mark on the camshaft or fuel pump sprocket, the mark will appear stationary when the speed of both engines is the same (or a multiple of an integer). The pulley will rotate at half crankshaft speed, but this will not affect the adjustment.
11. Warm up the engine (the cooling fan should turn on) and let it idle, proceed as follows.
12. Move the fast idle lever on the fuel pump toward the flywheel until it touches the fast idle adjustment screw (see illustration).
9.12. Bosch fuel pump adjustment screws: A - Fast idle lever; B - Throttle lever; 1 - Fast idle speed adjustment screw; 2 - Idle speed adjustment screw; 3 - Deceleration frequency adjustment screw; 4 - Screw for adjusting the maximum engine speed.
13. Check that the high idle speed is within the specifications. If necessary, loosen the lock nut and rotate the adjusting screw to achieve the specified fast idle speed. Finally, tighten the lock nut.
14. Turn off the engine and disconnect the tachometer.
15. Now you need to adjust the fast idle cable. This is done as follows.
16. The engine must be warmed up to normal operating temperature, and the fast idle lever must be in its original position (touch the idle speed adjustment screw, but not the fast idle adjustment screw). Gently pull the fast idle cable.
17. Position the tip on the cable so that the distance between the edge of the fast idle lever and the tip is 6.0±1 mm (see illustration).
9.17. Adjusting the length of the fast idle cable on the Bosch fuel pump (thermal actuator): A - Fast idle lever; C - Cable end; 1 - Fast idle speed adjustment screw; x = 6.0 mm.
18. Once the tip is correctly positioned, tighten the screw.
19. When the engine has cooled down, check that the cable moves the fast idle lever so that it touches the fast idle adjustment screw. Warm up the engine to normal operating temperature and recheck that the "x" dimension between the edge of the fast idle lever and the end of the cable matches the specified data (see illustration 9.17). If this is not the case, the thermal drive is probably faulty.