A method of sealing at least one gas leak in an engine including the steps of locating at least one gas leak, pre-mixing an alkyl polyether composition and a crosslinking composition to form a dental impression material, or applying the alkyl polyether and crosslinking components to an engine in the vicinity of at least one located gas leak, and repeating the aforementioned steps as many times as neccessary to seal a substantial number of gas leaks in an engine.