Change Oil After Using Fogging Oil?

A reader asks: “I used AMSOIL Engine Fogging Oil on my car last year before winterizing it. Now it is time to re-start it again. My question is: Should I change the oil before starting the engine or should I start the engine first in order to get rid of fogging oil residue? Second question: If I change the oil first, is the new oil contaminated by the fogging oil residue still left inside the engine?”

Answer

If you are changing the oil anyway, start the the car and give it a brief warmup run and then change the oil. This way the fogging oil is purged and you are starting with a clean slate. Whenever possible, an engine should warmed-up before changing the oil. This puts contaminants into suspension before the oil is dropped.

If you changed oil just prior to storage, fogging oil will not contaminate the engine oil or cause any issues.

By the way, changing oil before long-term storage is always a good idea. Used oil holds acids and combustion byproducts that may not be friendly to engine internals. New oil offers a fresh anti-corrosion additive package that will protect engine components.