What should be used to clean carbon deposits in an air compressor?

First, assess the degree of coking.

Common symptoms of coking in air compressors include elevated oil temperature, darkened oil, accelerated blockage of the oil filter element, increased exhaust temperature, and reduced oil‑line flow. Before cleaning, first determine whether the issue is mild oil sludge or severe carbon buildup, and inspect the oil circuit, thermostatic valve, oil filter element, and cooler.

Available cleaning methods

• Light oil sludge: Replace the oil and perform a circulation flush.Drain the old oil completely, replace the oil filter element, and add new oil or flushing oil as specified in the equipment manual. Circulate the system for the recommended duration, then drain it, and finally fill with the designated lubricant.
• Moderate carbon buildup: Use an oil‑system cleaning agent.Select an oil‑soluble cleaning agent that is compatible with the lubricant and sealing materials, and after shutting down and depressurizing, circulate it through the oil system to loosen sludge and carbon deposits, then drain it completely.
• Severe carbon buildup: disassemble, inspect, and clean.If the oil circuit, the internal components of the main engine, or the cooler are visibly clogged, it is not advisable to rely solely on chemical circulation; instead, qualified personnel should disassemble and inspect the system, perform cleaning, and replace any damaged parts.

General steps for fuel system cleaning

• Shut down the equipment, disconnect the power, and tag the system to confirm that system pressure has been relieved and the equipment temperature has dropped to a safe operating range.
• Record operating conditions, inspect the oil level, oil condition, filter differential pressure, and exhaust temperature, and identify the source of contamination.
• Drain the old oil, making every effort to completely remove any residual oil from the oil cooler, oil lines, and oil tank.
• Replace easily contaminated components such as the oil filter element and the oil separator element to prevent contaminants from the old filters from re-entering the system.
• Add the permitted cleaning medium and circulate it in the prescribed direction and for the specified duration; during circulation, monitor pressure, temperature, and leakage.
• Completely drain the cleaning medium, and if necessary, flush again with fresh oil to minimize residual cleaning agent.
• Add the specified grade of lubricant or a confirmed compatible lubricant, check the oil level, then perform an idling test run before gradually applying load.

Cleaning Precautions

• Do not mix different types of lubricants or cleaning agents indiscriminately; before use, verify compatibility with seals, hoses, and the oil itself.
• Avoid using highly corrosive solvents of unknown origin to prevent damage to the rotor, bearings, seals, and oil‑system coatings.
• After cleaning, all residual liquid must be completely drained; any remaining cleaning agent may cause foaming, emulsification, temperature rise, or re‑coking.
• Waste oil and used cleaning fluids shall be collected and stored, then handed over to a qualified entity for proper disposal, and must not be dumped indiscriminately.

Methods for Reducing Re‑coking

• Inspect the oil color, oil level, and filter element condition on a regular schedule, and promptly investigate the cause if the oil darkens rapidly.
• Control the operating temperature, keep the cooler clean, and avoid prolonged high-temperature operation to prevent accelerated oil oxidation.
• Keep the intake air clean to minimize the ingress of dust and oil‑mist contaminants into the lubrication system.
• Establish maintenance records that document oil changes, filter replacements, cleaning schedules, and operating parameters, enabling early detection of abnormalities.