Inspection and Maintenance — General Description (Opel Vectra A)

1. Wipe the engine completely, clean all components and inspect them for signs of wear. Each component should be inspected and, if necessary, replaced or repaired as described in the relevant Chapters of this Section.

2. Replace the main and connecting rod bearings if it is not known when they were installed.

3. If you are in doubt about replacing a component that is still serviceable, calculate the time and cost that would be required if the component failed earlier than expected.

4. Gaskets, seals and O-rings should all be replaced. Also, the flywheel, cylinder head, main and connecting rod bearing cap bolts should be replaced, as they are subject to high stress.

5. Replace the engine plugs while they are still easily accessible if they are leaking. Knock out the old plugs with a hammer and flat chisel or punch. Clean the plug seats, coat the new plugs with sealant, and hammer them into place.

Source is on the website (OpelBook.ru)