How many miles on the timing chains typically 4.0L

[LubeMan1]

just wondering how many miles you guys see on a 4.0L before you have to worry about timing chains going bad???

 

[rmcknight]

about 100K on old style (< 2001 model).
never have to worry on >= 2001 model, unless you start to hear the death rattle.

 

[Maniak]

Just for clarification for anyone not familiar with the 4.0l motors..

The above post from rmcknight is about the 4.0 SOHC motors..

The older 4.0 OHV motors from earlier generations didn't have to worry about timing chains...


And for just another anecdote of info.. our 2006 4.0 sohc has just over 230k miles on it.. Motor is still quiet.

~Mark

 

[Exproblems]

just wondering how many miles you guys see on a 4.0L before you have to worry about timing chains going bad???

The "rear" timing chain tensioner on my 2005 SOHC V-6 recently crapped out on me at 96K. I bought the vehicle with 82K on it.

 

[Joscibo]

I bought my 04 with a bad engine it crapped out at 164,000.

 

[Mike-in-Maine]

our 2003 4.0l had 133k on it when we bought it and was smooth and quiet. At around 170k it started to make some chain noise. It got progressively worse until at 189k it sounded so bad it was frightening to drive. We're talking chain noise so bad it sounded as if the whole vehicle was about to fall apart.

Changed all the chains, guides, etc at 190k.

 

[2000StreetRod]

timing chains vs guide assemblies

Since LubeMan1 has a 2002 model I assume he has the SOHC V6 with the improved timing chain related components that were incorporated in 2002 and later models. In my opinion the chains themselves could last more than 500K miles if the plastic guide assemblies didn't break or the tensioners didn't fail. That's when the chains may actually break. I think the 2005 higher mileage Mustangs with the improved timing chain components are starting to experience guide assembly failures since the right guide assembly was never reinforced with metal on the traction side.

It's a shame that Ford left the guide assembly weak that requires pulling the engine or transmission to replace. I suspect if the suggested periodic maintenance is performed (oil & filter changes, synthetic oil, functional thermostat, normal driving) the improved components should last at least 200K miles. My old style right guide assembly broke at 150K miles.

 

[tubeless]

My 04 had to be replaced by 118000. The Harmonic balancer was rotten also.

 

[LubeMan1]

about 100K on old style (< 2001 model).
never have to worry on >= 2001 model, unless you start to hear the death rattle.

My X is a late model 2001 (I think Nov 2001) which is classified as 2002 model year..Still good to go on the timing chains?? and yes it's 4.0L SOHC with 128,000 on it just picked it up in Aug of this year.

Thanks for all the responses..

 

[sfhess]

I replaced the lower oil pan gasket in my 2002 XLT to fix a leak. I found some pieces of white plastic in the pan. The car has no history of any major engine work performed (Carfax, dealer records, Ford STAR report). Mileage is 92,000. No noises, it starts and runs perfectly. Should I be concerned?

 

[Exproblems]

I replaced the lower oil pan gasket in my 2002 XLT to fix a leak. I found some pieces of white plastic in the pan. The car has no history of any major engine work performed (Carfax, dealer records, Ford STAR report). Mileage is 92,000. No noises, it starts and runs perfectly. Should I be concerned?

If you found pieces of white plastic in the oil pan, then take a look a post #7 by 2000StreetRod and you'll see a long section of white plastic (left side of chain) in his photo of the timing chain and tensioner/guide. That white plastic you found could be from one of those, not good.

 

[rmcknight]

Sfhess, The plastic pieces wont be from that pictured one, the other one is far more likely, it has a long curved top (that holds the oil on the chain) a ridiculous design, this becomes brittle and breaks off and gets munched. But it doesn't effect the tension at all - it does eventually all get caught in the pan and the oil pickup filter, and causes oil restriction, and that is not good at all. So your lucky you found it.

By the way, you can hear / feel most of the issues with the chains if present at about 2800 rpm and at idle.

Keep changing the oil and filter regularly, at least every 5 on mineral and 10 on full synthetic. And the 6 quarts of the transmission oil / filter every 30K to 50K.

 

[sabasigh]

I bought a 2000 Explorer back in '06 with 114k miles. Now at 250k it rattles, but still gets close to 17mpg, doesn't use any oil.

Hardly ever rev'd it over 3000-3500rpm though.

 

[Exproblems]

Keep changing the oil and filter regularly, at least every 5 on mineral and 10 on full synthetic. And the 6 quarts of the transmission oil / filter every 30K to 50K.

Changing the oil on a regular basis is a good thing to do, but it won't necessarily save you from a timing chain guide/tensioner failure. Since I owned my Ex 2yrs 7 months at breakdown (bought with 82.5k, broke down at 96.2K), I put around 13,700 miles on it and had changed the oil and filter 7 times in that time and mileage period and my rear timing chain guide/tensioner went bad on my vehicle resulting in a motor replacement. I use nothing but high quality oil and filters and it didn't save me from this problem. Also, I never had or heard a prior timing chain rattle in the engine prior to failure, just heard a very brief (1 second) racing sound at engine start up that didn't sound quite right. My chain break down problem happened as I went to start the engine one morning, never got the engine to fire up after that and all 3 right bank cylinders had "zero compression".

 

[2000StreetRod]

pre-oiler

The spring in the left and right timing chain tensioners is not strong enough to keep the chains taught. It is barely (if that) adequate to keep the chains from slipping. The slack side of the chains are only taught when there is hydraulic pressure. When a guide assembly breaks there is more slack in the chain and a greater chance of it slipping. The guides are more apt to break when there is no oil present and more friction. I installed a pre-oiler to eliminate "dry starts" and reduce the chance of the guides breaking and the chains slipping. The chains will not slip when the crankshaft is pulling the camshaft via the chains. The chains are most likely to slip when the engine is decelerating or when rotating at very low rpm (as in cranking) when there is slack on the traction side.

 

[rmcknight]

Hi Exproblems,
nothing saves you forever from the guide failure, but frequent oil changes will help as the oil pressure will be higher and cleaner. It will never fail without complaining first (often for years). in your case i suspect a sprocket bolt may have let go, not worn out guides, that will happen without warning on startup due to the extra force on the chain then. (the slow speed is not liked as it pulls and pushes on the chain). there is nothing you can do to predict that.

 

[LubeMan1]

Does this sound familar to timing chain failure??

http://youtu.be/QKC22xiFZ2U

 

[Exproblems]

Hi Exproblems,
in your case i suspect a sprocket bolt may have let go, not worn out guides, that will happen without warning on startup due to the extra force on the chain then. (the slow speed is not liked as it pulls and pushes on the chain). there is nothing you can do to predict that.

Hi and I don't know about the sprocket bolt being my problem, neither my mechanic nor the Ford dealership that change the motor mentioned anything about a sprocket bolt letting go. They both suggested that the timing chain "jumped it's time" or skipped over the gear teeth and out of time. Seems like a slack in the chain issue to me, but I don't know much about these plastic tensioners other than what I have learned through this site. Any way, it's over and I'm closing in a my first 100 miles on the new, remanufactured engine.

 

[rmcknight]

neither my mechanic nor the Ford dealership.

Doesn't surprise me, once the sprocket lets go, its a new head, you cant do 1 head without the other, so thats 2 heads, once you do that, and the new timing gear, then you may as well put in a reman with a 12 month warranty.

And thats what a mechanic / business will always do, as then he doesnt have any risk of the comebacks.

 

[rmcknight]

Sounds like exhaust / metallic, but its very hard to appreciate it off a recording - could be the cats. you could take the exhaust off and run it?

Timing chain rattle will be more pronounced with cold engine first start in the morning and is quite obvious.