Simply, a timing or cam belt is what connects the top and bottom ends of your engine, operating many different parts at the correct times. The engine water pump is also commonly driven from this belt.
Some engines have timing chains instead of belts and can have more than one belt or chain.
If a chain stretches, or a belt snaps, serious damage can occur to your engine, potentially requiring a new engine!!!
Different manufactures specify different replacement intervals for their belts and belt-driven components. The most common intervals are 5, 7 or 10* years, or around 100,000 miles*
Engines with chains can commonly run longer.
Land Rover's TDV6 oil pump is driven by the timing belt. These are prone to failure.
It is recommended to replace these with a modified genuine unit at the same interval.
New Genuine TDV6 Oil Pump
Land Rover 2.2 TD4 engine, found in Freelander 2 and Range Rover Evoque.
Below is a chain-driven example, found in the Landrover Defender TDCI Puma engine
*Generic ages/distances. Please enquire for model-specific details