When to Replace Timing Belt

I have a 2003 Subaru Forester with 44,000 miles. How will I know when to replace the timing belt? Is it more a question of miles or age?

It’s a question of both miles and age. Your manual probably recommends something like a 105,000 mile interval. However, the belt is now 8 or so years old. That’s about the right time to replace it, even with low miles.

That information is contained in your owners manual, usually found in the glove compartment…

Junkyards are full of Subaru’s once owned by people who lost their owners manuals or never learned how to read them…

  1. Open glove compartment
  2. Find booklet entitled Subaru Maintenance and Warranty
  3. Read text relating to timing belt:
    “Change timing belt at 105,000 miles or 105 months, whichever comes first.”

(Translation: The timing belt should be changed 8 3/4 years after the vehicle was put into service)

The belt and the car were likely produced and assembled back in the fall of '02. This means the belt is well over 8 years old if the production date was in that period.
(Production plate is on driver’s door jam.)

On an interference fit engine I would never allow a belt to exceed 6 years of age and would err on the side of caution and do it at 5.
There are other factors besides miles and age that can contribute to belt failure. Extremes of heat and cold, moisture and oil vapors from oil seals, any instances of engine overheating and so on.

Unless the engine has expired before that mileage is reached…

It is due. However with low mileage you have to make a choice on your risk as you will pay the few thousand to fix a motor with snapped belt.

My now deceased grandmothers 98 Forester is still in the family with 60k miles and on the original timing belt. No snap but if does it will be bummer but not the end of the world…

That’s an interesting data point…an original timing belt on a '98 vehicle and still going strong. Makes me wonder who can claim the record for oldest/highest mileage timing belt.