My wife has an 02 explorer 4x4 4.6l. Recently it started making a very noticeable ticking noise at idle. I have replaced both idler pulleys as well as the belt tensioner pulley. The noise is still there. I am now thinking that the noise has something to do with the timing chain. Has anyone had this problem and if so how dificult or expensive is it to fix?

 

I think timing chain issues had to do with just the 4.0 engine, I never read about timing chains effecting the 4.6 V-8 engine, but I could be wrong.

do you know if it's more of a slight knocking sound instead of ticking? If it's a knocking sound, its probably your rods that have to be realined as I know theres a TSB out for that.

If it is a ticking and not the timing chain, maybe your fuel injectors are getting clogged up. Run a good bottle of fuel injector cleaner, maybe that will get that sluge out of your injectors as I know they can become noise if there dirty.

One other thing I thought of, maybe one of your spark plugs is not firing all the way making a ticking sound as it sparks. where the plugs and wires changed at all since brand new?

 

I guess the best way to describe the is sound is it sounds almost like a deisel. It also could be described as the sound something would make if the fan was hitting something. It has gotten kinda loud. I placed my hand on each valve cover and could feel the noise if that makes any sense.

 

I just got done with the same issue, my 2001 4.0 V-6 was ticknig for almost a year....I did eveything we could think of, injectors, timing adjusted, spark plugs replaced. I ended up replacing the engine. The ticking was an issue with my engine, my mechanic (my uncle) said that if I had gotten it in when it started we could have avoided replacing the engine

 

I beleive that I have found the problem. Today I pulled the passenger side valve cover (where the noise was coming from). I looked at the timing chain and it seems fine. I did notice that the noise appeared to be the lifter followers slapping the lifters. Does anyone know the "technical" name of these followers? I am planning on replacing them next weekend.

 

I decided to share this because I'm surprised how it all worked out. This may just be unique to my truck, but maybe not. My Explorer had the issue of having coolant slowly leaking or seeping into the oil cavity. This started happening after the 100k mileage mark. This is a one owner vehicle and well maintained. I solved this issue (different story), but the result of the coolant leaking into the crankcase was sludge buildup, which caused my engine to tick and rattle excessively at startup and low idol. I used a stethoscope to try and find the zone of the tapping and it was top side middle and front area near timing covers. All over the top side really, but nothing that made me think it was rod knocking. I decided to try flushing the sludge out and considered the commercial options. I chose to drain two quarts of oil out of the oil pan and pour in two quarts of diesel fuel. I know, I've read a lot of threads talking about both sides of this technique, but I was willing to gamble. I let the engine idle for 30 minutes before turning it off and letting it sit for an hour to drain back into the pan as much as possible before changing the oil and filter. Literally 10 minutes into the diesel-flush the engine stopped ticking and clanking. It went as silent as a sewing machine and I was very surprised and skeptical and let it keep idling for the last 20 minutes as I stared at the engine and listened with the stethoscope waiting for the noise to return, which it didn't. The oil was pretty clean when I did this and it came out pretty black, but no globs or chunks. Well, I'm several thousand miles beyond this treatment and my engine is still so quiet that I find myself hanging my head out the window and stops to be certain that the clanking, ticking is really gone. I drive this truck pretty hard, always have. It's running great and I'm amazed how this freed up the components that were clogged, or journals that were plugged. Whatever it did I'm damn glad that I gave it a try. I'll update my post if there are any issues as I drive this truck about 50 miles daily.