hi iv got a 200tdi defender that has the timing belt riding forward .its a 1990 engine its done about 200,000 miles .when I first had it I changed the belt and the original belt had been wearing on the case .since then iv had no problems .I changed the belt for a trip around the highlands .and since then the problems come back . iv used the correct tools to tention the belt and the belt was a daco kit has anybody got any imfo on why this is happening and how to cure it .