Thanks Steve and Phil

I have just applied gasket sealant so hope that fixes it......It says to leave for 24 hours to dry so will know by this time tomorrow if it has fixed it!!

Phil....I have the same, a 2001 2.0 Zetec. I have only had her 2 weeks. She has had one owner from new and he was an old boy who had it serviced by Ford every 8,000 miles. She is now on 112,000 miles. What are these engines like? I have looked an seen the performance figures seem very much like the 1.8 Zetec, only the 1.8 Zetec has a far better fuel consumption? I have done 2 little mods which I hope have improved performance but cant really notice anything. Firstly I fitted Bosch Super 4 plugs and secondly I have run a 3" pipe from the intake of the airfilter housing all the way to the lower grill thus giving a forced air feed.....Not noticed any difference though in performance? Also I have seen an ST170 second hand exhaust for sale, it is the standard Ford one.....Would my 2.0 Zetec benefit from this?

Thanks again guys.