Compressor & Valve Replacement, Pressure Switches & Service Valves

FIGURE 13:

3. COMPRESSOR CYLINDER HEAD GASKET AND VALVE PLATE REPLACEMENT

Removal

1. Remove and drain the compressor.

2. Remove the cylinder head bolts and remove the cylinder head. Use a thin blade screwdriver or putty knife to loosen the head.

3. Remove the valve plate and gaskets. Use a thin blade screwdriver or putty knife to loosen the plate and gaskets (Fig. 13).

CAUTION: Do not remove the valve from the valve plate (Fig. 13).
Installation

1. Clean and inspect the cylinder head and valve plate surfaces and check the condition of the valve on the valve plate. Replace worn or damaged components if necessary.

2. Lubricate the head gaskets and valve plate with clean refrigerant oil.

FIGURE 14:

3. Assemble and install the gaskets, valve plate, and cylinder head.

4. Tighten the cylinder head bolts to 30-34 N-m (22-25 ft.lbs.) in the sequence shown in Figure 14.

5. Fill the compressor with oil. Refer to the compressor refilling procedures in the appropriate manual.

FIGURE 15:

4. RECEIVER-DRYER PRESSURE SWITCHES

The receiver-dryer on all but LeCar models is equipped with either a low pressure switch (A) or both a low and high pressure switch (Fig. 15).

The low pressure switch protects the compressor in the event of a pressure drop in the system. The high pressure switch protects the compressor against extreme pressure buildup in the system.

Both switches are connected in series to the compressor and will open the compressor feed circuit if system pressure becomes too low or too high.

Switch usage is as follows:

^ Alliance - has low pressure switch only.

^ Fuego - has high and low pressure switches.

^ 18i - has high and low pressure switches.

Switch cut-off pressures are:

^ Low pressure switch opens circuit at 3 bars (43.5 psi).

^ High pressure switch opens circuit at 28 bars (406 psi).

FIGURE 16:

S. SERVICE VALVES

Two types of compressor service valves are used on Renault vehicles.

Alliance models are equipped with three-position service valves (Fig. 16).

Fuego, 18i and LeCar models are equipped with standard Schrader service valves.

Three Position Valves

The three position valves must be mid-positioned for evacuating, charging, discharging or checking system pressures (Fig. 16 view C). The backseated position (view B) is for normal operation after servicing. The front seated position (view A) isolates the compressor allowing compressor removal for service without having to discharge and recharge the system.
Turn the position valve stem counterclockwise to the backseated position and clockwise to the front seated position. The valve service port
(1) is open only in the mid-position.

CAUTION: Do not mid-position the valves until all service or test hoses have been connected to the valve service ports.
Schrader Valves

Schrader valves have no provision for isolating the compressor. If the compressor must be removed on Fuego, 18i and LeCar models, the system must first be discharged; then evacuated and recharged afterward.

Service Valve Seals

O-ring seals are used with both types of service valves.

These seals should be inspected during system service and replaced if worn or damaged. Lubricate replacement seals with clean refrigerant oil before installation.

On three position valve, the seals are located in the compressor connector fittings on the valve.

NOTE: Two different seals are used on three position valves. The suction (low side) valve seal is larger in diameter and has a flatter cross section. The discharge (high side) seal is smaller in diameter and has a round cross section.

On models with Schrader valves, the O-ring seals are located in the connector fittings on the compressor hoses.