4.0 SOHC timing chain

[sd02FX4]

My 2002 4.0 sohc with 117,000 miles has just started to make what I believe the timing chain rattle noise. It has always made a half second or so rattle on some cold starts for the 2000 miles I have owned it. It does it at idle when cold, but I only notice it in gear, not park/neutral, and I have to be stopped next to a wall or something for the sound to bounce off of. (It does not sound anything like a diesel like some really bad ones I have seen, though) It will also do it noticeably around 55-65 mph (2000-2300ish rpm) up and down a 2 mile 6% or so grade I travel daily. Its not as bad downhill, and I don't notice it really on flatland when its warmed up all the way.

I'm curious as to how long people have driven with this, or if it has ever ended in catastrophic failure... If its just noisy, I don't care about it. I remember seeing a service bulletin that said this doesn't affect engine durability, but another one (update maybe?) that said nothing about durability. I have also read that changing to higher quality oil has gotten rid of it in some cases, and I know the prev owner had the oil changed right before I bought the truck, and put cheapo stuff in it.

If anybody has been driving with it for 80,000 miles just fine, or if it killed your engine after doing nothing about it, I'd like like hear about it.

I don't know if it's a serious issue that neds attention or if I'm just being paranoid.
Thanks for your input.

 

[Big Jim M]

First place

My 2002 4.0 sohc with 117,000 miles has just started to make what I believe the timing chain rattle noise. It has always made a half second or so rattle on some cold starts for the 2000 miles I have owned it. It does it at idle when cold, but I only notice it in gear, not park/neutral, and I have to be stopped next to a wall or something for the sound to bounce off of. (It does not sound anything like a diesel like some really bad ones I have seen, though) It will also do it noticeably around 55-65 mph (2000-2300ish rpm) up and down a 2 mile 6% or so grade I travel daily. Its not as bad downhill, and I don't notice it really on flatland when its warmed up all the way.

I'm curious as to how long people have driven with this, or if it has ever ended in catastrophic failure... If its just noisy, I don't care about it. I remember seeing a service bulletin that said this doesn't affect engine durability, but another one (update maybe?) that said nothing about durability. I have also read that changing to higher quality oil has gotten rid of it in some cases, and I know the prev owner had the oil changed right before I bought the truck, and put cheapo stuff in it.

If anybody has been driving with it for 80,000 miles just fine, or if it killed your engine after doing nothing about it, I'd like like hear about it.

I don't know if it's a serious issue that neds attention or if I'm just being paranoid.
Thanks for your input.

I'd be looking at the exhaust system! Sounds to me like rattle from one of the heat deflectors or even something inside a muffler..
At that milage the CHAINS in your engine should be Ok.. And believe me it is a bitch to change them out.. pulling the engine is a must.
Big JIm

 

[sd02FX4]

It is the chains rattling around.
I am going to try replacing the tensioners first. I see the rear tensioner by the #3 spark plug, but can anyone tell me where the front tensioner is on this engine?

 

[Birdmanman]

Look under the thermostat housing.Also if you need to change the rear chain you can do it by taking out the transmission and removing the flywheel.Behind the flywheel are the 2 access points you need to get to the jackshaft sprocket and guide bolts.Ive done it.There are pictures from someone else who did it on the explorer forum.

 

[wintermute]

…I'm curious as to how long people have driven with this, or if it has ever ended in catastrophic failure... If its just noisy, I don't care about it…If anybody has been driving with it for 80,000 miles just fine, or if it killed your engine after doing nothing about it, I'd like like hear about it…

I'm very curious about this as well. My '03 Edge (with 49,500 miles!) exhibits what I believe to be the chain rattle, which is only really heard during accelerating to freeway speed in the morning when the engine is still on the cool end of the scale. (~2300 rpm as well) Backing off the throttle for a slower run to 60 quiets things down.