the harsh hot weather in the Southwest destroys anything that’s rubber the dry
heat dries out and crystalizes rubber making brittle weak and vulnerable to
failure. This type of driving condition is very severe and very hard on
vehicles whereas the cool damp climate of the Northeast is very mild on rubber
components. Replacing the timing belt should be done between 5-6 years or
between 60-90 miles whichever comes first. One important thing to understand
when having the timing belt replaced is it's rarely just replacement of the
timing belt only!
That’s because there are other parts associated with timing
belts function that must be inspected to ensure lone trouble free operation. For example; most water pumps are driven by the timing belt these are
prone to leakage and bearing failure as mileage increases replacing it while
the timing belt is removed is very common practice.
There are idler bearings
and tensioner bearings that become overheated due to stretched belts slapping against them causing the outer surface of the belt to melt to the pulleys. There are also various different seals that are
hidden behind the timing belt pulleys that are prone to leakage allowing oil to saturate and ruin the belt.