No, unless your vehicle was in an accident covered by your insurance policy which caused the damage to your fiance’s engine, his insurance company would not pay for the damages let alone declare the car a total loss. Mechanical problems not caused by damage from an insurable incident are not normally covered by an insurance policy.

Typical coverage for engines and mechanical issues are covered under warranties or third-party additions.

A car is totaled out when it has been damaged in what is described by the terms of your policy as an insurable incident and the repairs would cost as much or more than what the vehicle is worth. If your vehicle has been in such an incident and you are having engine issues due to it, then contact your insurance company to make a claim through your physical damage coverages of collision or comprehensive.