Does my car need a new timing belt

2004 Ford Explorer did not use a timing belt. It used a timing chain and as long as it is running properly no special service to the chains is required.

The 4.0L engine has 4 timing chains, and the 4.6L has 2 timing chains. So the concern for things to wrong is that there are fiber guides that the chain runs on in-order to keep the proper tension that do wear out. I would suggest finding some one or a shop and have the valve train inspected if there are a lot of miles on the vehicle. That way they can inform you of the condition of the timing chains and what noises to listen for in the future. Once you know all this it just needs to be done once so you know.

Why do people tell you that the chains need changing? Do they rattle a lot? If so you probably need to have them replaced along with the guides and tensioners.

If the rear guides, tensioner, or chain needs to be replace, look for another engine. The engine has to come out of the vehicle to service those parts in the rear.

Only the V6 4.0 requires removal of the engine. The 4.6 can be done in the yard.