automobile control cables The cleaning of surface oil stains and the restoration of insulation performance need to be comprehensively considered in combination with the characteristics of cable materials, the type of oil stains and the usage scenarios. The following is an explanation from two aspects: the selection of cleaning agents and the restoration of insulation performance:

I. automobile control cables materials and oil contamination effects

automobile control cables is usually composed of conductors (copper/aluminium), insulating layers (PVC, rubber, TPE, etc.) and sheaths. Surface oil stains (such as engine oil, gear oil, hydraulic oil or environmental contaminants) may cause:

The insulation layer swells and ages, reducing its voltage resistance capacity.

Oil stains adsorb dust to form conductive channels, increasing leakage current.

Long-term residual corrosion of insulating materials shortens the service life of cables.

Ii. Principles and Recommendations for Selecting Cleaning Agents

The cleaning agent should meet the following requirements: highly efficient in removing oil stains, no damage to the insulation layer, low residue, and safe and environmentally friendly. The specific selection should be based on the type of cable insulation material and the composition of oil stains.

1. Cleaning agent compatibility based on insulating materials

Insulating material properties Applicable cleaning agents Contraindicated cleaning agents

PVC (polyvinyl chloride) is oil-resistant but easily swells by strong solvents such as neutral detergents, isopropyl alcohol (above 75%), anhydrous ethanol gasoline, toluene, and banana water (strongly swells).

Rubber (nitrile rubber, EPDM) has good oil resistance but is afraid of strong acids and alkalis, weakly alkaline solutions (5% sodium carbonate), silicon-based cleaners, concentrated sulfuric acid, and concentrated hydrochloric acid (corrosion).

TPE (thermoplastic elastomer) has good weather resistance but is easily eroded by solvents. Deionized water + nonionic surfactants (such as Tween 80), strongly polar solvents (DMF, DMSO)

2. Selection of cleaning agents based on the type of oil stains

• Mineral oil (engine oil, lubricating oil) : Non-polar oil stains require non-polar solvents (such as white spirit, n-hexane) or emulsifiers containing surfactants (such as neutral industrial cleaners).

• Synthetic oils (PAO, ester oils) : They have relatively low polarity, and weakly polar solvents (such as a blend of isopropyl alcohol and surfactants) can be selected.

• Environmental oil stains (a mixture of dust and grease) : Water-based cleaners (such as diluted neutral dishwashing liquid) are recommended, which can both remove oil and dust.

3. Safety and Operation Suggestions

• Prefer water-based or alcohol-based cleaners (such as 75% ethanol), which are low in VOC (volatile organic compounds) and low in toxicity;

Avoid strong corrosiveness (strong acids/alkalis) or strong swelling solvents (such as carbon tetrachloride);

Before cleaning, a test is required: Apply the cleaner to the concealed area of the cable, let it stand for 10 minutes, and observe whether there is swelling, discoloration or softening.

Iii. Methods for Restoring Insulation Performance

After cleaning, the insulation performance needs to be restored through drying, testing and repair. The key steps are as follows:

1. Thoroughly dry

After the oil stains are removed, residual moisture or cleaning agents may cause a decline in insulation. It is necessary to:

• Natural drying: When the ambient temperature is 25℃ and the humidity is less than 60%, let it stand for 2 to 4 hours.

• Forced drying: Use a hot air gun (≤60℃) or an oven (50~70℃) for purging to prevent the insulation layer from aging due to high temperature.

• Vacuum drying: For precision cables, a vacuum environment can be used to accelerate solvent evaporation.

2. Insulation performance testing

• Megohmmeter measurement: Use a 500V or 1000V megohmmeter to measure the insulation resistance between the core wires of the cable and between the core wires and ground (the standard is usually ≥100MΩ).

• Withstand voltage test: Apply 1500V AC voltage for 1 minute. If there is no breakdown or flashover, it is qualified.

• Visual inspection: Observe whether the insulation layer is damaged (such as cracked or thinned) due to cleaning. If so, it needs to be repaired.

3. Insulation repair (if necessary)

• Minor damage: Wrap with insulating tape (such as PVC electrical tape) or heat shrink tubing;

• Severe damage: The damaged section needs to be removed, the insulation layer re-extruded (professional equipment required), or the cable replaced.

Iv. Precautions

When cleaning, avoid vigorous wiping to prevent mechanical damage to the insulation layer.

Batch cleaning can be carried out by soaking (it is necessary to ensure that the cables are not damaged and the cleaning agent is not strongly corrosive).

For cables that have been stored for a long time, after cleaning, a small amount of insulating grease (such as silicone grease) can be applied to prevent moisture and dirt.

Summary: automobile control cables oil stain cleaning should select the appropriate cleaning agent based on the insulation material and the type of oil stain (water-based/alcohol-based is preferred). After cleaning, ensure performance recovery through drying and insulation testing, and repair damage if necessary. The key lies in balancing the oil removal efficiency with material compatibility to avoid secondary damage.