Thick as molasses. Quiets noisy lifters and tick tick sounds helping to keep wear and tear down.best to use with a fresh oil and filter change.Thus if you use a good amount, you may need to adjust your oil viscosity at oil change.Example: if you are using five quarts of 5w30 you can go to four 5w20 with one quart of this additive if replacing all 5 quarts of oil.