If it's very difficult or impossible to turn, that indicates a problem. This could be due to:
* Low oil pressure: Lack of lubrication will cause significant friction.
* Bent valve: A bent valve can interfere with camshaft rotation.
* Seized bearings: Worn or damaged camshaft bearings will create significant resistance.
* Broken timing belt (if applicable): A broken timing belt will prevent the camshaft from turning. The Metro uses a timing belt.
* Other mechanical issues: Something else could be binding or jamming within the valve train.
If you're encountering significant resistance, do not force it. Further damage is likely. Have a mechanic diagnose the problem before attempting to turn the camshaft again.
