This is how we approach this issue...
Most modern vehicles require the cambelt replacing at the manufacturers recommended interval. What we have learnt over the many years of dealing with this area of vehicle repair is that the belt isn't always the only component that fails, causing the timing to slip and resulting in a collision of engine components (pistons and valves).
For many years we have fitted cambelt kits which included new belt, guide bearings and tensioners. More recently, following a number of water pump failures, we are now recommending replacement of the water pump especially if it runs on the timing belt. When you think of it, if your timing belt replacement is five years and you only replace the belt kit you are then expecting the water pump to last a further five years (ten years in total) if you then think that when we fit the new belt we put the correct amount of tension for a new belt then the bearings in the water pump have to withstand this as if it is a new component, unfortunately most pumps don't and within 18 months the pump fails and this can result in the belt slipping. The consequences of this is that the job needs to be carried out again and if it has slipped this will also then include the cylinder head and valves as well which can result in a bill in excess of £1000.
For replacement intervals and estimates on what it would cost to replace your cambelt please call us on 0121 472 3848 and have your vehicle registration number handy.