10/09/2026
Why would a ISO VG 220 gear oil that has run normally for 3 years suddenly develop excessive foam?
Don’t assume the oil has simply “gone bad.” As gear oil ages, anti-foam additives can be depleted. Water, contaminants, additive degradation, low oil levels, high return-line velocity, or air entering the system can all contribute to excessive foaming.
Why does it matter? Excessive foam can accelerate oil oxidation, interfere with proper lubrication, increase gear wear, and shorten oil service life.
🔧 What should you check?
1️⃣ Check the oil level and top up with the same grade if needed.
2️⃣ Remove water and solid contaminants through filtration or oil purification.
3️⃣ Restore the anti-foam additive if compatible with the oil formulation.
4️⃣ Check return lines and seals for possible air ingress.
When water and contamination are part of the problem, precision oil purification can be an effective part of the solution. AITAI provides precision oil purifiers for industrial lubricating and gear oils, with optional bubble-removal functions for applications affected by air entrainment.
