Note: A new O-ring will be required during installation.
Note: The following procedure only applies to models with the F8Q 620 engine (with Bosch fuel pump and without air conditioning).
Removal
1. The thermal actuator is located on the left end of the cylinder head (refer to the accompanying illustration).
2. Partially drain the cooling system as described in Chapter Maintenance.
3. Loosen the screw or nut and remove the end cap from the cable on the fast idle lever on the fuel pump (refer to the accompanying illustration).
4. Pull the cable housing off the bracket on the fuel pump.
5. Unscrew the thermal actuator from the cylinder head and remove the actuator together with the cable. Remove the sealing ring (refer to the accompanying illustration).
Installation
1. Install the actuator in place using a new O-ring and tighten it.
2. Fill the cooling system as described in Chapter Maintenance.
3. Insert the cable housing into the bracket on the fuel pump.
4. Insert the cable into the fast idle lever and place the end on the cable, do not tighten the screw or nut yet.
5. Adjust the cable as described in the following paragraphs.
Checking and adjusting
Note: During this procedure, it is necessary to measure the engine speed. A conventional tachometer, which operates from the 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 this is usually not available to the motorist. If you cannot adjust the idle speed by ear or using the tachometer on the dashboard, you can use the following recommendations.
- a) Buy or borrow an appropriate tachometer.
- b) Entrust the work to a Renault service station or another specialist.
- c) Use the comparative method. The stroboscope is operated by a gasoline engine running at the desired speed. If the stroboscope is aimed at a mark on the camshaft or fuel pump gear, 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.
1. Warm up the engine (the cooling fan should turn on) and let it idle (refer to Section Checking and adjusting idle speed and deceleration speed), proceed further as follows.
A - Fast idle lever; B - Throttle lever; 1 - Fast idle adjustment screw; 2 - Idle speed adjustment screw; 3 - Deceleration speed adjustment screw; 4 - Maximum engine speed adjustment screw
2. Move the fast idle lever on the fuel pump toward the flywheel until it touches the fast idle adjustment screw (refer to the accompanying illustration).
3. Make sure that the fast idle speed is within the specifications given in Specifications. If necessary, loosen the lock nut and turn the adjustment screw to achieve the setting specified in Specifications fast idle speed. Finally, tighten the lock nut.
4. Turn off the engine and disconnect the tachometer.
5. Now you need to adjust the fast idle cable. This is done as follows.
6. 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.
A - Fast idle lever; C - Cable end; 1 - Fast idle adjustment screw; x = 6.0 mm
7. 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 (refer to the accompanying illustration).
8. Once the tip is correctly positioned, tighten the screw.
9. When the engine is cool, check that the cable moves the fast idle lever so that it touches the fast idle adjustment screw. Warm the engine to normal operating temperature and check again that the "x" dimension between the edge of the fast idle lever and the end of the cable corresponds to the specified data (refer to the illustration above). If this is not the case, the thermal actuator is probably faulty.