when does the timing belt usually go out on a 99 ford explorer? 138k on mine, and still works.?

There is no timing belt on your '99 Explorer. It either has ONE timing CHAIN, if it's equipped with either the 4.0L OHV V6, or the 5.0L V8. If it's equipped with the 4.0L SOHC, you have THREE chains on the timing drive system.

60k is the usual recommendation. Whether you have a problem when it breaks depends on whether you have an interference or non-interference engine. If the timing belt (chain, gears, whatever the engine uses) breaks, the camshafts stop rotating and some valves will stop in the open position, pushed down into the cylinder. If the engine is interference, the piston will collide with the open valves on its next trip up, causing expensive damage. If the engine is non-interference, it will merely stop running and you get a new timing belt on. Nothing collides with anything. Check with a dealer and see what they have to say about the engine, although you're so far past any recommended belt change that they'll try to talk you in for one.

A '99 Explorer does not have a timing belt. Instead, it has a timing chain. There are two different versions of the 4.0l engine: an overhead valve type with one chain, and a single overhead cam type with three chains.

Ford had some noise problems with the latter type, but the first type is very dependable.

for my area, all the linked pulleys and the tensioner ought to have been replaced. I ran a Ford Mondeo for ten years, and on the 2nd cambelt substitute, i turn into recommended to alter all the kit on that end of the engine, which includes the water-pump as this is cambelt-pushed. I caught to the Ford advice re-cambelt substitute periods which turn into 80,000 miles or 5 years, whichever got here first and having had the motor vehicle from new, mine turn into replaced on the 5 year and then 10 year periods .

Some vehicles have timing belts others have timing chains. You probably have a timing chain. The only problem timing chains have are, they will stretch and cause your vehicle to jump time. Some timing belts will have plastic coating on the links to help them run quieter, this plastic sometimes breaks off and will cause the timing to jump. It is hard to give a mileage on timing chains. The timing belts will tear off cleats and usually last around 60,000 to 70,000 miles. Check with your dealer to find if you have a belt or chain.

Puzzled is right, your explorer doesnt have a belt, it has a chain, some never fail! I've got 230,000 on mine and it is still going strong. So don't worry about your timing chain

You know it is just a matter of time really. I changed mine as I was going to drive across the nation.

I have known people to never change it and not have a problem but if it goes the results can be costly.

Explorers don't have timing belts.

i own a repair shop,and it should have done went out on it,the mileage on it should have got it,they should be replaced every 50-60 thousand miles on any vehicle,id replace it before it breaks,its much easier this way and if it breaks it may do some damage to it,but its time to change it,good luck,i hope this help,s.

In your owners manual is should show the recommended change intervals. Usually around 80,000 or 100,000 miles is recommended