My (main dealer serviced) always shows the oil over MAX by about 10-20mm after three services. Doesn't seem to have done it any harm - so far. It's a petrol.

Is yours a diesel?

Worth asking them to check the oil for contamination. If fuel is somehow leaking into the sump then eventually the engine will run on its own sump oil, scarey!! Otherwise some coolant fluid could be getting in there. A check for contaminants is the very least the dealer could do. Worth the trip back there, after you have booked it in. Cheers Concrete

Overfilling engines with oil is bad for them. Our X reg 1.6Zetec Focus handbook says 'Never fill above MAX mark', probably for a very good reason. Its capacity is 4.25litres.

When I change the oil and filter, usually in summertime, I pour off 1litre from a 5l container and put in the rest. This brings the level nicely between the MAX and MIN mark. By winter, it is nearing the MIN mark and there it stays because the less oil, the quicker the engine warms up. I only top it up with 500mls when it is actually at the MIN mark. At 120,000 it is requiring three such top-ups between changes, which are done every 10- 12,000m or so, irrespective of time (could be up to 2yrs as it doesn't do 12,000m a year) so the engine is still in very good condition.

So take it back to the garage and tell them to do it right.