H hussamadeniMember Hydrometer to check Specific gravity is the simplest way.Sp Gr of common Flds1. Solvents & fuels : 0.6 - 0.7 Aprox2. Min oil (Lubes) : 0.79 - 0.89 Approx3. Synthetic oils : Upwards of 1M Hussam Adeni 5/25/059:38 AM