During cold soak procedure, which action is prescribed?

• A. Motor engine for 60 seconds
• B. Idle engine for 2 minutes
• C. Run engine at full power for 30 seconds
• D. Shut down engine completely

Answer: (A)

When an engine has been sitting cold, the oil is thick and needs a moment to reach all the moving parts. Briefly rotating the engine primes the lubrication system, builds oil pressure, and circulates lubricant to bearings and other critical components before the engine starts under load. Doing this for about a minute ensures lubrication is established quickly and helps reveal any early faults while there’s no heavy demand on the engine.

Idle-running for a longer period wastes time and still doesn’t achieve as rapid a buildup of oil pressure. Running at full power on a cold engine is risky and can cause damage before lubrication is fully established. Shutting the engine off would defeat the purpose of priming the system.