I have a MK2 2005 Focus TDCI LX. Recently it has started to make a clicking/ticking noise while the engine is running. It usually happens at around 1200 to 1800 RPM, above or below this it does not seem to make the noise.
The mileage on the car is 123k and I have serviced it regularly every 6k miles since I bought the car in 2011 when it had 88k miles on it. At every service I have replaced the air, oil and fuel filter.
With the most recent service I bought 10w40 semi synthetic oil. I have a feeling that this oil is the problem, or that the timing belt is about to give up the ghost soon.
Thanks in advance for your help.