GM 5.0/5.7L pre-1996 Engine break-in procedures:
- Use of Lucas Break-in Additive or AC/Delco engine oil supplement is recommended for start-up. **
- Prime engine for at least one minute with an air/oiler system or the engine’s oil pump driven by a drill & adapter or other external source (Do Not use the starter to rotate engine as this will wipe off the assembly lube).
- Complete all necessary “tune-up” procedures including setting ignition timing prior to starting the engine for the first time. (Excessive “cranking” of new engine with starter is not recommended).
- GM recommends a 30 minute “run-in” of the engine at high idle (1200 rpm or more) to break-in the camshaft. Check for leaks, watch oil pressure and engine coolant temperature, and then change the engine oil and filter after initial “run-in”. If road testing, drive in both city and highway conditions if possible, but do not exceed 90kph/3800rpm.
- A follow-up oil and filter change after an additional 500-1000 km should also be made before returning to the regular engine maintenance schedule.
** marine engines should use genuine Mercruiser engine oil or HD30 engine oil (10W-30 is not recommended for pre-roller cam marine engines).