What are simne problems you will have if your timing chain needs to be replaced?

May be its problem with timing chain and it has to be inspected and replaced.Or its possible that timing chain is got misaligned.

There are few help,links provided related to timing chain assembly and dis-assembly. Go through it and confirm proper inspecting of timing chain.

Click the required help link below:----How to Replace Timing Chain Cover & Seal on Audi A4 ? http://repairhelpcenter.blogspot.com/2011/11/how-to-replace-timing-chain-cover-seal.html
----------1982 Toyota Pickup: Set ignition timing, engine overheating, timing chain issue, dist off? http://whatisbyme.blogspot.in/2012/05/1982-toyota-pickup-set-ignition.html
----------How to Remove Timing Chain Cover and Seal on Toyota Previa?

http://technoanswers.blogspot.com/2011/12/how-to-remove-timing-chain-cover-and.html

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How to Remove Timing Chain and Gears on Toyota Previa?

http://technoanswers.blogspot.com/2011/12/how-to-remove-timing-chain-and-gears-on.html

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Ford Mondeo ST220 camshaft Timing specifications? http://technoanswers.blogspot.in/2012/02/ford-mondeo-st220-camshaft-timing.html
------------Replacing Timing Chain Cover For 2009 Ford?

http://repairhelpcenter.blogspot.in/2012/03/replacing-timing-chain-cover-ford-2009.html

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Timing Chains & Front Cover Removal on 2008 Ford Taurus? http://repairhelpcenter.blogspot.in/2012/03/timing-chains-front-cover-removal-on.html
----------How to Replace Timing Chain Cover, Chain, Sprockets, & Seal On Ford Taurus? http://repairhelpcenter.blogspot.in/2012/03/how-to-replace-timing-chain-cover-chain.html
---------How to Replace Timing Chain & Sprockets on Ford Windstar? http://repairhelpcenter.blogspot.in/2012/03/how-to-replace-timing-chain-sprockets.html
---------Timing Chain & Sprockets Replacing on Ford, Mercury and Lincoln? http://fordrepairhelp.blogspot.in/2012/03/timing-chain-sprockets-replacing-on.html
----------How to Replace Timing Chain & Sprockets on Ford Edge and Lincoln MKX? http://howtobyme.blogspot.in/2012/03/how-to-replace-timing-chain-sprockets.html
------How To Replace Timing Chain, Sprockets & Front Cover on Ford Expedition and Lincoln Navigator? http://repairhelpcenter.blogspot.in/2012/03/how-to-replace-timing-chain-sprockets_356.html
---------Timing Chain, Sprockets, Front Cover & Seal removal for Ford Mustang? http://schematicsdiagram.blogspot.in/2012/03/timing-chain-sprockets-front-cover-seal.html
---------How to Replace Timing Chain on Buick LaCrosse? http://howtobyme.blogspot.in/2012/03/how-to-replace-timing-chain-on-buick.html
---------These details will help.For more help keep updated.Thanks.

It is personal taste. Some places recommend that timing CHAINS be replaced every 90K-100K, but others drive until there is some change in their engine performance that would indicate the timing chain and then change it. Since you have the timing chain and not the timing belt it is up to you.

Generally, I will replace timing chains IF I have to pull my engine out of the car for any reason, but won't change it at set intervals.

timing chains let you know when its time to change them as they rattle but if you do a rebuild at say 200k then obviously change the chain/tensioner

As timing chain accumulate mileage, chain stretch, sprockets wear out and set the valves off timing. Most chains go up to 100000 miles or more, but not always. As a rule when there is more than about half inch of play between the gears on a V6 or V8, it is the time for a new timing chain and sprockets.
It is unusual for a timing chain to accumulate 200000miles, but I remember a car, with broken timing chain with only 160000miles on it.
Signs of worn out timing chains are:
Rough idle.
Sluggish performance and poor economy.
Sudden engine performance change including the inability to start the engine.
Intermittent backfire through the intake manifold.
Inconsistent ignition timing or a clattering noise coming from the front of the engine.
It is a good idea to replace the water pump (coolant pump), and the thermostat while replacing the timing chain.
The cost of the replace of timing chain is at least +$1300, but if is to bad, we pull out engine and replace both guides. In this case might cost more.
Please do not be mad with me. I'm a certified dealer, and I'm trying to give you the necessary information to help you to deal with the problem.

1998-2003 To Remove:

1. Remove or disconnect the following:
   • Crankshaft pulley and hub
   • Drive belt tensioner
     
     
   • Timing chain cover bolts
     
     
   • Timing chain cover and gasket
2. Install a bolt in the end of the crankshaft CAUTION
   Do not install the crankshaft balancer bolt or a bolt longer than 1 inch or damage to the crankshaft threaded hole will result.
   
3. Rotate crankshaft until the number 1 piston is at Top Dead Center of compression stroke.
4. Make sure that the alignment marks are aligned with the tabs on the timing chain tensioner.
   
   
5. Measure distance between hole in bracket and unworn surface of timing chain tensioner shoe. NOTE: If distance between the hole and unworn surface of timing chain tensioner is greater than 0.314 in (8 mm), replace tensioner, timing chain and sprockets.
   
6. Remove timing chain tensioner bolts.
7. Remove the timing chain, timing chain tensioner and camshaft sprocket at the same time.
8. Remove the crankshaft sprocket using special tool J 22888-20A or equivalent.
9. Remove crankshaft sprocket alignment key.

NOTE: If any camshaft components are being replaced to correct a noise problem, all camshaft drive components must be replaced.
To Install:

1. Install the crankshaft sprocket alignment key.
2. Install the crankshaft sprocket using special tool J 5590 or equivalent.
   
   
3. Compress the timing chain tensioner spring and insert a pin into the tensioner hole to retain the tensioner shoe.
4. Install timing chain and timing chain tensioner (do not tighten tension bolts).
5. Align the crankshaft and camshaft timing marks with the tab on the timing chain tensioner.
6. Tighten the timing chain tensioner bolts.
   • Torque to: 18 ft lbs (24 Nm)
7. Tighten the camshaft sprocket bolt.
   • Torque to: 96 ft lbs (130 Nm)
8. Remove pin from timing chain tensioner hole.
9. Remove bolt from end of crankshaft. CAUTION
   Inspect the timing chain cover for warping or damage. Replace if needed.
   
10. Clean all timing chain cover mating surfaces.
11. Install or connect the following:
    • Timing chain cover to the engine block
      1. Ensure that the gasket is installed properly in the groove in the timing chain cover
    • Timing chain cover and make sure it fully seated on the alignment dowel pins
    • Timing chain cover bolts
      1. Torque to: 97 inch lbs (11 Nm)
    • Drive belt tensioner
    • Crankshaft damper hub and the crankshaft pulley

Chain. It doesn't need replaced unless it has a problem. Chains don't have a service replacement interval.

100 000

need to have a shop fix it asap.if the chain breaks or skips timing your entire could possibly need to be replaced.replacing a serpentine belt tensioner is fairly cheap and easy

Timing chains do need to be replaced but they can typically go much longer between being serviced than can timing belts. The chain will stretch out over time and can 'jump' timing. If you have an interference engine then that can prove disastrous as the piston can crash into the valves.

Its not terribly common for a timing chain to jump timing but not impossible. I have a vehicle with nearly 120k with a timing chain and its never been replaced and is still in good shape, I have another vehicle with 170k also with a timing chain that has never been replaced.

If it were me and I was going to be doing some work in that area and had easy enough access to the timing chain, and the mileage was getting up there, I would replace it. Timing chains typically also have a tensioner, so if you replace it, dont forget this item.

If you have a chain, there is NO replacement interval. ALL 4 cylinder Highlanders have timing chains.