When dose ford recommend to changing timing chain on 4.6 ford Explorer? It nothing about this in ford Schedule Service that you can find at ford.com.

 

To my knowlege there is no set time for this as most modular V8s will go well past 200,000 miles before needing the chain and guides replaced and at that point Ford dosen't care as the vehicle is well past it's warrantee. From my experience the time when the chain usually fails is around 150/160,000 miles if the engine has only had marginal maintenance but, with good maintenance they seem to last over 300,000 miles.

 

Ok thanks :-) Then I don´t have to worry just jet..But do you know if it big thing to do? I have read somewere that in 4.0 you have to remove the engine to do this.

 

On the 4.0 that might be the easiest way but some have done it in the truck, with a lot of work.
The 4.6 can be done without removing the engine.