How to Fix Oil Leakage in an Air Compressor: 9 Key Checks

Oil leakage in an air compressor can lead to performance issues, increased wear, and potential system failures. Identifying and addressing the root cause early can prevent costly repairs and downtime. Below are nine key checks and solutions to help diagnose and fix oil leakage in air compressors, including screw air compressors.

1. Inspect the Air Compressor Filter

🔍 What to check:

• Look for damage, defects, or dirt buildup in the air filter.

• Check if the intake pipe is kinked or deformed, which can cause pressure imbalances.

✅ Solution:

• Replace damaged or clogged filters immediately.

• Ensure the intake pipe has a minimum inner diameter of 15.9 mm for proper airflow.

2. Examine the Return Oil Pipe

🔍 What to check:

• Bends, kinks, or obstructions in the return oil pipe.

• Ensure the return oil pipe slopes downward from the air compressor to the engine crankcase.

✅ Solution:

• Use a minimum inner diameter of 12 mm for the return oil pipe.

• If oil is pooling, reposition the pipe for smooth drainage.

3. Check Cylinder Liner and Piston Rings (For Screw Air Compressors)

🔍 What to check:

• Wear and damage on the cylinder liner and piston rings.

• Improper assembly of piston components.

✅ Solution:

• Replace severely worn parts to restore proper sealing.

• Ensure correct installation and alignment of piston components.

4. Maintain the Cooling System

🔍 What to check:

• Air-cooled compressors: Look for oil, soot, or dirt buildup on the heat sink.

• Water-cooled compressors: Check cooling pipes for blockages, rust, or restrictions.

✅ Solution:

• Clean heat sinks and replace damaged cooling components.

• Ensure coolant flow is at least 5 liters per minute at normal engine operation.

• Use pipes with a minimum inner diameter of 9.5 mm for proper coolant flow.

5. Monitor Air Compressor Operating Temperature

🔍 What to check:

• Ensure the water temperature does not exceed 93°C.

• Check air valves in the air reservoir for proper operation.

✅ Solution:

• Equip the system with an automatic exhaust valve.

• Install an air dryer before the air reservoir to remove moisture and reduce oil contamination.

6. Check for Air Leaks in the Brake System

🔍 What to check:

• Air leakage when the brakes are not in use should not exceed 6.9 kPa per minute.

• When using the brakes, leakage should not exceed 20.7 kPa per minute.

✅ Solution:

• Inspect the entire air system for leaks and seal any loose connections.

• Verify that the unloading system is functioning properly.

7. Measure Engine Crankcase Pressure

🔍 What to check:

• Excessive crankcase pressure can force oil leaks through seals and gaskets.

• A loose or lifted dipstick may indicate high crankcase pressure.

✅ Solution:

• Replace or repair the crankcase ventilation system.

• Check for clogged ventilation filters and clean or replace them.

8. Verify Engine Lubrication Pressure

🔍 What to check:

• Compare the oil pressure at the air compressor inlet with the manufacturer’s specifications.

✅ Solution:

• If the pressure is too low, check for oil pump failure, clogged oil lines, or incorrect oil viscosity.

9. Use the Correct Lubricant

🔍 What to check:

• Using low-quality or incorrect oil can cause excessive leakage and wear.

✅ Solution:

• Replace with manufacturer-recommended lubricants suitable for your air compressor type.

• Ensure proper oil levels to avoid excessive pressure buildup.

Final Thoughts

Oil leakage in an air compressor can be caused by filter blockages, improper pipe routing, worn components, cooling system failures, high crankcase pressure, or incorrect lubrication. Regular inspection, maintenance, and using high-quality lubricants can significantly reduce the risk of leaks and improve the efficiency of your compressor.

Tip: If oil leakage persists after troubleshooting, consult a professional air compressor technician for a detailed inspection!

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