During overhaul, why are disassembled engine parts degreased with mineral spirits solvent rather than water-mixed degreasers?

During overhaul, why are disassembled engine parts degreased with mineral spirits solvent rather than water-mixed degreasers?

• A. Water-mixed degreaser residues may cause engine oil contamination in the overhauled engine.
• B. Mineral spirits evaporate faster.
• C. Water-based degreasers remove oil too slowly.
• D. They require special disposal.

Answer: (A)

The key idea is avoiding any moisture or residue that could contaminate new oil. In an overhaul, parts must be as clean and dry as possible so the lubrication system isn’t polluted by cleaners or water left on surfaces. Water-based degreasers can leave water residues or emulsified oil films on parts. Those residues may mix with new engine oil once the engine is reassembled, risking contamination and potential lubrication problems. Mineral spirits are non-aqueous and dissolve oil effectively without introducing moisture, and they tend to evaporate cleanly, leaving parts dry and free of oily films. This reduces the chance of contaminating the fresh oil during reassembly. While disposal of solvents is a consideration, the essential reason for choosing mineral spirits here is to prevent water-containing residues from contaminating the engine oil.

The key idea is avoiding any moisture or residue that could contaminate new oil. In an overhaul, parts must be as clean and dry as possible so the lubrication system isn’t polluted by cleaners or water left on surfaces.

Water-based degreasers can leave water residues or emulsified oil films on parts. Those residues may mix with new engine oil once the engine is reassembled, risking contamination and potential lubrication problems. Mineral spirits are non-aqueous and dissolve oil effectively without introducing moisture, and they tend to evaporate cleanly, leaving parts dry and free of oily films. This reduces the chance of contaminating the fresh oil during reassembly.

While disposal of solvents is a consideration, the essential reason for choosing mineral spirits here is to prevent water-containing residues from contaminating the engine oil.