Engine Protect is an add-on cover which provides protection against damage to engine and its parts due to ingress of water, which is common during monsoon or due to hydrostatic lock, leakage of lubricating oil, damage to gear box, etc.
Damage to engine due to any of the above reasons is not payable under standard car insurance policy. Normally this cover is available as an add-on for vehicles which are less than 5 years old.
However, many insurers have package insurance policies including such add-ons as standard covers for specific brands of high-end cars, for a maximum of 5 years life of those cars.