Dodge Durango 2003 a rattle sound in the motor like a lifter

There are several types of noises that can come from the top end of a motor, so without any specifics it's impossible to say what is causing your rattling. It COULD be lifters, but it could be a bad timing chain. A mechanic is the best place to get the source of the noise identified. If your Durango has the 4.7L motor, they do have a poor timing chain design, namely it uses plastic guides and tensioners on the timing chain. Those can wear out and allow slack into the chain which can make a good tick in the engine. If the motor's got some miles on it, the lifters may be gunked up. Seafoam may help, but if the motor's worn it's only a matter of time before it goes. It's not the easiest engine to access either, it sits well back in the engine bay, so removing the valve covers is a small challenge. You can try replacing lifters and see if it improves anything, and adjusting valve lash while you're in there. But if the problem is with the timing chain or chain tensioners, the only fix is to remove front of engine and replace. Dodge does not consider the timing chains a "servicable item", so didn't make it the easiest thing to replace. However it can be done with engine in vehicle, after pulling radiator and core support. Check for OBD trouble codes, when lifters go you may start to see codes related to timing. (same with timing chain). When you see codes for knock, problem is getting severe, and if engine shuts down on it's own due to knock sensor, then the end is nigh. You're then looking at a rebuild or replacement engine.