I often wonder about when to change the timing chain on any vehicle. I've watched videos where the chain had to be replaced as soon as 40,000 miles. Some people recommend that it be replaced every 50,000 miles and definitely before 100,000 miles as a preventive measure. Some people with my car (2002 Mustang GT - 71,000 miles) had to change their chain at 75,000 miles. Surely these chains last a lot longer than this. Who would want the expense of changing a chain every 50,000-100,000 miles? Anyway, I've noticed on my ODB scan tool that my Mustang's timing on #1 cylinder varies from 9 degrees to 45 degrees while my 2014 Xterra (48,000 miles) varies from 14 to 34 degrees - these figures are from live data at varying speeds. I don't know if I should freak out over this or if my BlueDriver is giving me inaccurate info. I don't have a timing light.
I've run several engines 300,000-400,000 miles on their original timing chains with no problems. If the timing chain system is designed properly and regular oil changes are performed it should last the life of the engine.
timing advance is supposed to vary with engine load.
If it is retarded then you need to do something.
Well, I'm not a professional mechanic but I do have a 2001 Mustang GT with 153K miles and I have no indications of timing chain problems. There are actually two chains on the 4.6 SOHC engine. If the car hasn't been abused and you take reasonably good care of it in the future, you can rest easy on the timing chains.
A timing light doesn't work because there are no timing marks. You can't adjust it anyway, the computer controls the timing.
I change out all timing chains at around 120,000 miles or whenever they start to make noise on cold start, whichever comes FIRST.
