I had a ticking noise twice in the old Escorts and both times it was the exhaust manifold. First time was the gasket, second time was the extractor flange separated from the extractor tube. The easiest test to do for this is get a small piece of tissue paper and hold it from the top with a few centimetres hanging freely and hold it close to all the joints and different spots around the exhaust system and see if it starts blowing around. If nothing shows up the first time try getting a mate to partially cover the exhaust pipe (this puts more pressure thru the system and makes any leaks easier to notice). Hopefully, problem found .