What is a Timing Belt?
All engines (except Mazda rotaries) have a crankshaft and a camshaft. The crankshaft ultimately turns the wheels of your car. The camshaft opens and closes engine valves. The camshaft has to turn at exactly half the speed of the crankshaft. Engine designers use the crankshaft to turn the camshaft. Some use a chain that looks similar to a bicycle chain and some use a cogged, rubber belt. The rubber belt should be called a cam belt, but people refer to it as a timing belt because it synchronizes or times the crank and cam together.
How often should the belt be changed?
Every manufacturer specifies the belt to be changed at a specific interval. Some say 60,000 miles, some say 80,000 miles or more.
What do we suggest?
I agree with Toyota and Subaru. They recommend 60,000 for vehicles equipped with a spring loaded tensioner and around 100,000 for hydraulic tensioners. Most manufactures went to hydraulic in the mid to late 90ís.
Do not play the odds. When a belt breaks, it will leave you stranded, you will have to be towed! In addition, many cars will experience substantial damage to the valves and head and sometimes pistons when a belt breaks. It gets far more expensive to repair the damage than to do the maintenance.
How often should the chain be changed?
There is no recommended mileage interval for a chain. Most of the time, chains will give an audible warnings long before it breaks. A belt will give you no warning!
Should I change the water pump with the belt?
I recommend it. It is cheap insurance rather than have to pay all that money over again.
How much should I expect to pay for this maintenance?
There are a 2 or 3 variables on how this job is done. Knowing Subaruís propensity
for leaking oil here is what I recommend during this service:
*Change timing belt
*New water pump with new thermostat and coolant
*New camshaft seals
*New crankshaft seal
*Reseal the oil pump if necessary.
*New tensioner and all new idler gears (3)
óAll of the above is done for $550 Most models, except turbos.
+Add $30 for new accessory belts.
Front view† of Subaruís 2.0 Turbo Dual Overhead Cam† timing belt.