Toyota Corona Engine Problems
Additives work best
CHECK the engine is a Toyota engine because Toyota was fitting the Holden 1.9-litre overhead-valve four-cylinder engine to the Corona at that time. The capacity you quote suggests yours has the ``misfire'' four in it. If it's a Holden engine the compression ratio was 8.7:1, but it's likely to be less than that now. If it runs well I'd continue to use unleaded with an additive.
Losing lead
ACCORDING to the government guide, your car cannot run on unleaded petrol without an additive, so the best advice is to run it on regular, or premium unleaded if you can afford it, and add a commercial lead replacement additive available from your servo.
Going over the top
YOU can cause a problem putting too much oil in the sump. The crankshaft hits the oil as it rotates, which can put extra load on the engine, reduce performance and increase fuel consumption. It can also cause the oil to froth and cause problems in the lubrication system. However, adding an extra 200ml probably won't have too much effect.