The 5.4 L , V8 engine in a Ford Expedition has ( 1 timing CHAIN to each cylinder head , so there are 2 timing CHAINS ) It doesn't have a timing belt
Timing chains are not a scheduled maintenance replacement unlike a timing belt. Timing chains usually don't need to be replaced unless there is a problem with the engine itself. Timing chains will last as long as the engine. This is from personal experience.
99 Honda passport has a timing belt.
The 2.5 litre V6 engine in a 1999 Mercury Cougar has ( 1 timing CHAIN to each cylinder head , so there are 2 timing CHAINS )
The '99 Toyota Rav4 2-door has a timing belt, not a timing chain.
timing chain
The valves can be bent when the timing belt breaks.
You match the timing marks on the sprockets with the marks on the belt...exactly.
Mostly it has a time belt 99% it has a time belt WRONG IT HAS A CHAIN !!
It has a timing chain and gears.
The benefit to replacing the timing belt on a 99 Toyota RAV4 is that it prevents catastrophic failure and it keeps timing accurate. As the belt wears, it may slip or break which can be very expensive to repair.
The '99 Chevy Prizm has a timing chain, not a timing belt, so it does not need to be replaced.