I've already read a few posts here that I found by searching for this topic. But I wanted to expound on my specific situation. My son was driving my 2002 Explorer, 4.0L, 200K+, yesterday, and it started making a clicking noise under the hood. It clicks in time with the engine running, but it doesn't sound internal to me. It's more like it's in some of the apparatus on top of the engine, fuel delivery system. It doesn't sound like a timing chain to me, but I could be wrong. Maybe I'm just trying to be optimistic, but the thing runs fine, and all of the gauges are normal. I'm going to drive it today to see for myself. Any other ideas besides the timing chain?

THANKS!!!

 

Can you easily hear the ticking with the hood closed? The fuel injectors will make a clicking noise, but it's usually faint enough that with the hood closed, unless you're really listening for that noise, you won't notice it.

-Rod

 

No I can hear it very well, even with the hood closed.

It was kinda dark when I took a look at it last night, and I was using the light from my cellphone. That was before I read the posts about the timing chain, and the tensioner, and whatnot. I drove it to work today, and I could visualize the noise I heard being the timing chain hitting the cover. I am still hopeful, however, it's something a little less involved....

 

Drove it 13 miles to work and 13 miles back home with no issue except the noise. It was pretty dark again when I got home, but I took this video with my cell phone:


http://vid943.photobucket.com/albums...204_182648.mp4


I actually walked around the front of the vehicle during the video, from right front wheel to left front wheel. The sound seems louder beside the wheel wells.

 

As I've learned about what is involved with replacing the timing chains in this engine, and I know where I think the noise is coming from, I'm afraid that the rear timing chain is the culprit. And I know that is the one that involves removing the engine to get to. I keep hoping someone will chime in and say, "Have you looked at the [insert $2 part of your choice here]? It could be that."

 

OK, I resigned myself to the idea that my noise was coming from the rear timing chain. I've been trying not to drive the vehicle much, but I have driven it several times back and forth to work. No symptoms except the noise, and I noticed it seems to downshift more than normal. Anywho, Friday when I left work, I noticed that the noise had stopped. It clicked Friday morning on the way to work, but all the way home, no clicking. This took me by surprise as I figured the noise would go on until I fixed it, or the timing chain failed. The noise stopping actually worries me more than the noise. I can't imagine why it would stop, unless the noise was coming from somewhere else. I've got to drive it again today, so we'll see how it goes....

 

I just finally noticed the link to the video and listened to it. That doesn't sound to me like what I've heard for the timing components. The noise you have sounds very much like it's related to the position of 1 particular cylinder, not someone random like a timing component with a bad tensioner.

I'd suggest you spend a bit more time, if the noise comes back, trying to narrow down which cylinder is related to the noise. You might due this by unplugging spark plugs, one at a time, to see which one seems to be in time with the tick, or by unplugging fuel injectors in the same manner. Once you identify the cylinder, then focus on things like exhaust manifold studs, spark plug, plug wire, injector, compression, etc.

-Rod