The smart answer is "before it breaks". The 4.6L-4V engine has two timing CHAINS with a tensioner driving the cams at a 2 to 1 ratio. The engine is an interference engine so if one or both of the chains break or come off the tensioner the engine is basically shot. This happened to me at 143K miles. I had the car serviced by the dealer I bought it from and there was no mention of a service interval for the timing chain, ever. I always got the recommend service depending on the miles on the Mark. Replacing the engine is expensive and Ford had a series of bad rebuilds which caused me much grief. I went through 4 engines before (1 lockup after 40 minute, 1 timing tensioner failure after 2 weeks and 1 crank failure after 3 months) I got a keeper. I have 198K on the 1995 Mark now and I still love it! Get a price to check it out and see if it's worth it. You may be able to "listen" for excessive noise in the chains using an "engine stethoscope" but you probably have not point of reference to base a decision one. 4 chains total. (2 timing chains and 2 cam chains) Replace tensioners and sprockets also.
If the timing chain on your Lincoln LS is worn out then it should be replaced. A worn out timing chain can jump a link, or more, and the engine will ultimately not be able to run. Normally the timing chain will last the life of the engine.
The timing chain does not have a recommended change interval and should last for the life of the engine.The timing chain does not have a recommended change interval and should last for the life of the engine.
timing CHAIN
it has a timing chain !
The timing chain does not require replacement unless it has failed.
at what milage should the timing chain be replaced on a 95 ford aerostar
Chain.
Timing chains are designed to last the life of the engine and are replaced when the engine is rebuilt.
You are correct that the SL2 uses a timing chain. However, since it uses a timing chain it does not need to be replaced as does the timing BELT. In general, a timing chain should last the life of the engine.
It is not necessary to change the timing chain. It should last way over 100,000 miles. Timing belt should be change at least at 90,000 miles or earlier as listed in your owner's manual.
according to the local dealrship where I live ,you don't have to.It has a timing chain ,not a belt.Other(newer)years you have a belt and you have to change it.
118d has a timing chain that requires no service or change during its lifetime.