312000779 - S050 CLIMATE CONTROL SYSTEM NOISY / (IN THE ENGINE COMPARTMENT)

Test results
0PRELIMINARY CHECKSAll OKProblems encounteredOperation
Connect the climate control system to the special recharging equipment and check the system pressures by carrying out the    See Test 5040OB AIR CONDITIONING SYSTEM OPERATION CHECK (PRESSURE)Check the wear condition and correct belt alignment and tensioning.Run the engine at idle speed with the A/C system off and check whether the noise comes from other auxiliary components (engine fan, water pump, alternator). Increase the rpm and check for vibrations.Move on to Step 21. Pressure level incorrect.2. Belt alignment/tension incorrect or belt worn.3. The noise comes from other auxiliary components (engine cooling fan, coolant pump, alternator).1. Move on to Step 12. Restore correct alignment/tension or replace the belt.3. Continue as indicated in the diagnostic test procedure.
1PRESSURE VALUES IN HIGH AND LOW PRESSURE CIRCUIT CHECKAll OKProblems encounteredOperation

Keep the recharging device connected and check the pressure levels in the system high and low pressure circuit with the compressor on and engine running:

  • pressure values low in high and low pressure circuit;
  • pressure values high in high and low pressure circuit;
  • check that the pressure values (high and low) during compressor operation do not pulse and that the circuit does not equalise slowly when the engine is turned off.
End of diagnosis1. Low circuit pressure values (insufficient coolant in circuit)2. High circuit pressure values (too much coolant in circuit)3. Pulsing circuit pressure values (compressor discharge valve permanently open)1. Flush the system and restore the correct charge of fluid and gas    Op. 0010T84 COOLANT FOR AIR CONDITIONING SYSTEM - DEHYDRATE AND REPRESSURIZE 2. Flush the system and restore the correct charge of fluid and gas    Op. 0010T84 COOLANT FOR AIR CONDITIONING SYSTEM - DEHYDRATE AND REPRESSURIZE 3. Replace the compressor    Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY
If the compressor is replaced because of a mechanical problem, remember to clean the entire circuit and change the drier filter.
2PIPE AND COMPONENT FASTENING CHECKAll OKProblems encounteredOperation
Check that the compressor and system pipes and components are correctly fastened.

Check the following, in order:

  • bracket fastening to the engine block;
  • fastening of pipes (by bands and spacers);
  • no interference between pipes and other components in the engine compartment;
  • condenser cleanlineness or damage (presence of mud, foreign bodies).
Also check for cracks in the compressor fastenings to the bracket on the engine block.		Move on to Step 31. Fastening of components incorrect.2. Interference in the engine compartment.3. Condenser obstructed or damaged.4. Also check for cracks in the compressor fastenings to the bracket on the engine block.1. Retighten fastenings to torque.2. Restore the correct layout of the pipes3. Clean or replace the condenser    Op. 5040A40 AIR CONDITIONING CONDENSER - R+R 4. Replace the compressor    Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY
3CHECKS TO CARRIED OUT WITHOUT THE COMPRESSOR ONAll OKProblems encounteredOperation

Checks to be carried out without the compressor on:

  • disconnect the service belt and check for contact between the armature and pulley;
  • with the belt disconnected, check for contact between the pulley and external elements.
  • check the wear of the pulley bearing by rotating the moving plate in both directions of rotation.
  • check whether the compressor magnetic coupling shows signs of overheating.
Move on to Step 41. Presence of contact between armature and pulley.2. Presence of contact between the pulley and external elements.3. Bearing worn.4. Signs of overheating on the compressor magnetic coupling.1. Replace the compressor    Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY 2. Remove the contact.3. Replace the compressor    Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY 4. Replace the compressor    Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY
If the compressor is replaced because of a mechanical problem, remember to clean the entire circuit and change the drier filter.
4CHECKS TO CARRIED OUT WITH THE COMPRESSOR ONAll OKProblems encounteredOperation

After restoring the correct connection of the service belt, turn the compressor on and off to check:

  • if the compressor magnetic coupling plate slips due to oil or grease on the plate (do this visually);
  • if slippage takes place between the compressor belt and pulley.
Move on to Step 51. Oil or grease on the plate.2. Slippage between compressor belt and pulley.1. Clean the oil or grease off the plate and find the oil leak.2. Replace the belt.
5CHECK FOR GAS LEAKS ON THE COMPRESSOR SIDEAll OKProblems encounteredOperation
With the engine started and the climate control system at the maximum speed (compressor button ON), place the temperature adjustment knob/button in the maximum cold position, move the probe of the leak detector near to the connector to be analysed and check for any leaks. If there is a leak, repeat the test to make sure that there really is a leak.Withdraw the pipes from the compressor and ensure that the o-rings on the pipes are correctly positioned.Check the condition of the pipe fastening threads on the compressor.With the engine off and the compressor off, bring the leak detector probe up to the compressor pulley near the shaft stem and rear cylinder head gasket to check for leaks. If there is a leak, repeat the test to make sure that there really is a leak.Also check whether the leak is located in other coolant system components.End of diagnosis1. Compressor pipe o-rings poorly positioned (pinching).2. Pipe fastening threads not intact.3. Leak located on shaft stem or compressor rear head.4. Leak located in other cooling system components.1. Reposition the compressor pipe o-rings correctly.2. Replace the compressor    Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY 3. Replace the compressor    Op. 5040A20 AIR CONDITIONING COMPRESSOR - R+R - INCLUDES FLUID LEVEL CHECK AND TOP UP IF NECESSARY 4. Eliminate the leak and restore the circuit to correct operation.
If the compressor is replaced because of a mechanical problem, remember to clean the entire circuit and change the drier filter.