Am having trouble on finding the marks to re place the timing chain on a ford expidition 99

The timing chain on a Ford Expedition works with the camshaft and crankshaft, turning them through sprockets. The alignment with the chain and its sprockets is very precise, so replacing the chain is a very precise and difficult procedure. The chain has its own cover that you must remove to access it. Consult your mechanic before working on the timing chain. The process can vary depending on the year and engine type. Professional maintenance is always recommended.

1. Removing the Chain Cover
   • 1 Disable the truck's ignition system by disconnecting the primary electrical connectors at the ignition coil pack. Disconnect the negative battery cable before you do this.
     
   • 2 Take out the spark plugs by unplugging their wires and removing them with a socket wrench and spark plug socket.
     
   • 3 Install a compression gauge into the Number One cylinder and use a breaker bar and socket on the crankshaft's damper bolt to turn the crankshaft. Turn it until the notch in the damper aligns with the TDC mark on the front cover and compression is noted on the gauge.
     
   • 4 Drain the engine oil from the truck into a pan by removing the oil pan plug and remove the oil filter with a filter wrench.
     
   • 5 Unbolt and remove the crankshaft pulley and vibration damper; mark their positions so they can be installed the same way. Avoid turning the crankshaft as you remove the damper.
     
   • 6 Remove all accessory brackets connected to the timing chain cover by unbolting them. This includes unbolting the power steering pump; set it aside with its hoses still connected.
     
   • 7 Disconnect the camshaft position sensor's electrical connector and remove the camshaft position sensor. Disconnect the electrical connectors for the crankshaft position sensor and knock sensor.
     
   • 8 Remove the front bolts on the oil pan and the socket-head bolt--the latter requires an Allen wrench. Disconnect the heater hoses and then unbolt and pull out the heater outlet tube.
     
   • 9 Separate the timing chain cover by removing its bolts. You may need to tap it with a soft face hammer if it's stuck.
     
   Changing the Chain
   • 1 Check and see that the timing marks on the camshaft, crankshaft and balance shaft sprockets are all aligned. If not, re-install the vibration damper bolt so you can turn the crankshaft clockwise to align the marks.
     
   • 2 Remove the camshaft sprocket's mounting bolt and the camshaft position sensor's drive gear. Compress the timing chain tensioner with a screwdriver, hold the tensioner in the retracted position with a drill or Allen wrench and pull the sprocketed chain off the camshaft.
     
   • 3 Turn the camshaft until the key is facing the 12 o'clock position (straight up).
     
   • 4 Place the replacement chain on the camshaft sprocket, turn the sprocket until its timing mark faces 6 o'clock (straight down), position the chain over both sprockets with their timing marks lined up and slip the sprockets on the camshaft and crankshaft.
     
   • 5 Install the camshaft position sensor drive gear by aligning its keyway arrow with the Woodruff key on the camshaft.
     
   • 6 Install the camshaft sprocket bolt, applying a non-hardening thread-locking compound to the threads, and tighten the bolt to 30 to 36 foot-pounds.
     
   • 7 Remove the drill or wrench from the timing chain tensioner and re-install all the other parts in the reverse order of removal. This includes adding fresh engine oil and a new oil filter.
     

You need to buy a professional grade timing chain manual

That is a big job and usually a challange for the pros

You can not work on anything on todays vehicles without
reference material.

Those days are gone for ever, once we left the 1970's

The chain links are marked or colored & the crank has to
be in the correct place, as well as the cams have to be held down
in the correct place

You need to replace the plastic chain guides & the tensioners
& know how to pin the tensioners to install the chains,thus a manual