By Jim Fitch
Practicing Oil Analysis Magazine
Even the very best motor oils cannot safeguard against sludge when free water is present. Within several minutes after starting an engine, the oil typically reaches the thermostat setting. This heat can drive off the moisture, even in cold winter conditions. However, it can sometimes take 15 to 20 minutes of continuous driving before the condensed moisture has dissipated.
When water accumulates in sooty used oil and remains in the engine for an extended time, the damage to the oil is irreversible. This is why short-trip “Aunt Minnie” drivers need to change their car’s oil more frequently.
How frequently? If you are a short-trip driver like me, consider performing a simple blotter spot test before a scheduled oil change in order to regulate the optimum oil change interval to your driving conditions and climate. If you see undispersed soot, characterized by an inability of the soot to wick outward into the card stock, this may indicate that you need to change your oil more frequently.