1. Low refrigerant level: When the refrigerant level is low, the air conditioning system cannot adequately cool the air, causing the engine to work harder and vibrate.
2. Faulty compressor: A faulty compressor can cause the engine to vibrate when the air conditioner is turned on.
3. Loose or damaged engine mounts: Loose or damaged engine mounts can allow the engine to move excessively when the air conditioner is turned on, causing vibration.
4. Malfunctioning fan clutch: A malfunctioning fan clutch can prevent the engine from cooling properly, causing the engine to vibrate.
5. Vacuum leak: A vacuum leak can cause the engine to run lean and vibrate when the air conditioner is turned on.
Diagnosis:
To diagnose the cause of the engine vibration when the air conditioner is turned on, the following steps can be performed:
1. Check the refrigerant level: The refrigerant level can be checked using a pressure gauge. If the refrigerant level is low, it should be recharged.
2. Inspect the compressor: The compressor can be inspected for signs of damage or wear. If the compressor is faulty, it should be replaced.
3. Check the engine mounts: The engine mounts can be inspected for looseness or damage. If the engine mounts are loose or damaged, they should be replaced.
4. Test the fan clutch: The fan clutch can be tested by turning on the air conditioner and observing the fan. If the fan does not engage or does not turn at the correct speed, the fan clutch should be replaced.
5. Look for vacuum leaks: Vacuum leaks can be detected by listening for a hissing sound or by using a smoke machine. If a vacuum leak is found, it should be repaired.
Repair:
Once the cause of the engine vibration has been diagnosed, the appropriate repairs can be performed. These repairs may include:
* Recharging the refrigerant level
* Replacing the compressor
* Replacing the engine mounts
* Replacing the fan clutch
* Repairing vacuum leaks
