http://www.autozone.com/addVehicleId,2579302/initialAction,repairGuide/shopping/repairGuide.htm?pageId=0900c152801decc0 This is for a 2000 don't know if it's the same as a 99 but might help
locate timing chain guides.
Timing chain.
No , the 5.0 liter V8 engine in a 1998 Mercury Mountaineer has ( 1 ) timing CHAIN
chain
In the 1998 Mercury Mountaineer : The 4.0 liter SOHC - V6 engine has ( 3 ) timing CHAINS The 5.0 liter V8 engine has ( 1 ) timing CHAIN
only when it begins to fail.
On a 2002 Mercury Mountaineer : The 4.6 liter V8 engine uses ( 2 timing CHAINS / 1 CHAIN to each cylinder head )
The 5.0 litre / 302 cubic inch V8 used in a 1999 Mercury Mountaineer has a timing CHAIN
How do i change the chain out of my 1998 mercury mountaineer transfer case
The 4.0 liter SOHC , V6 , has ( 3 ) timing chains and the 5.0 liter V8 has ( 1 ) timing chain , if that's what you are asking ?
timing chain diagram for 1998 Nissan altima
Timing chains are designed to last the life of the engine. They are normally replaced during a complete engine overhaul. Unless the chain becomes noisy no maintenance is required.