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Timing Chain Going Out (V6)


New Member
December 22, 2010
Reaction score
City, State
Dallas TX
Year, Model & Trim Level
2003 XLT
I have a 2003 Explorer with the 4.0L V6. It has about 115K miles on it. It sounds terrible when started cold, with a very loud rattle that I was told is the timing chain. The idle is a bit rough, but it gets better when warm. It doesn't sound perfect when warm, but much better than when its cold.
I'm told it will cost about $3K to fix, which I don't really want to spend.
Can anyone estimate how long the engine will last if I just live with the noise ? Could it last a while, or is the loud noise a sign that it is about to die ?
Appreciate any advice you can give. Thanks.


Staff member
Elite Explorer
May 26, 2009
Reaction score
City, State
Greenville, SC
Year, Model & Trim Level
00 Sport FI, 03 Ltd V8
2WD or 4WD?

Try to locate the source of the sound using a hose, tube or mechanic's stethoscope. Your 2003 should have the improved guides and tensioners so 115K miles is a little early for failure. If the sound is coming from the lower, center front of the engine then it's probably the primary chain tensioner or the balance shaft chain tensioner if you have 4WD. Members rarely experience engine failure from the primary tensioner failure. If the sound is coming from the upper left front then your left guide assembly has probably failed. If it is coming from the upper right rear then your right guide assembly has probably failed. Eventually the chain will slip and your exhaust valves on the failed bank will strike the pistons. That could happen tomorrow or years from now.