Timing Belts
Note: Your mileage may vary.
Timing belts are flat ribbed belts that drive the cam shaft on the engine. Like all the drive belts of your car timing belts must be periodically replaced. For most cars the interval is every 90,000 to 105,000 miles on most newer cars, and should be listed in your owners manual. If you have a Toyota, talk to me about it; many Toyotas do not have a timing belt interval. They will, however, need to be replaced at some point.
When the timing belt breaks the engine stops and will not run until the belt is replaced. On some engines (interference engines) the valves can hit the pistons or the other valves causing engine damage that is very expensive to repair.
There are many factors that can shorten the life of timing belts. These include short distance driving, stop and go driving, oil on the belt (the biggest cause of premature failure), failing idler bearing, or water pump (on cars with timing belt driven water pump.)
If you buy an experienced car with 90,000 to 100,000 miles, it is important to establish whether the timing belt has been changed. It is not always possible to tell this just by looking at the timing belt.
Timing belt jobs can be relatively labor intensive and since oil leaking onto the timing belt will require a new timing belt we nearly always recommend replacing the front engine oil seals (located directly behind the timing belt) at the same time. On some cars the timing belt drives the water pump and on these we usually recommend changing the water pump as part of the timing belt job.
These factors can cause Matt's Import Haven timing belt estimates to seem more expensive than a "simple" timing belt job. Experience has taught us that taking these extra steps to do the job right will save you the expense and inconvenience of having to do it over prematurely.