Odd rattling noise during low RPMs

[BrianDye]

Another new trait my 2006 is showing:

First off, of course I searched the "death rattle" where the timing chain issue comes into play, this sounds NOTHING close to that.

Family had a Taurus once that kind of sounded like this, and I think it ended up being something related to an exhaust heat shield or cover of some sort, but im currently sick as a dog, stuck in bed for the time being so I cant really go outside and look around right now.

It only happens for instance in the morning when I first start it, and put it in reverse or drive but have my foot on the brakes, so the RPMs are a bit lower than idling in neutral or park. It goes away with ANY increase in RPMs.

Seems to be more of an annoyance than anything. Are there heat shields or anything on this exhaust system that tend to break off or anything?

(4.0 V6)

 

[banditxp]

seeing how your in a rust state its a gonna be a heat shield most likely. there are a few. one is hidden pretty good at the front of the gas tank ont he pass side up close tot he frame/floor to shield the fuel filter.. also what i do it jsut start banking on stuff under it and bank on the exhause too. sometimes a clamp or muffler can rattle.

 

[BrianDye]

I'll check that out, but it seems the noise is coming from the front, I haven't been able to get out there and replicate the noise while outside the truck yet, but I'll check that out too.

 

[Tech By Trade]

There is one on top of each cat as well. They have crappy little bead welds on them that like to break. Have a good look at the exhaust manifolds too. i know the V8 is more notorious but my 4.0 did manage to break the rear stud on the driver side.

 

[BrianDye]

Im thinking it was the dried up chunks of mud everywhere under there. I finally decided to get off my butt for the first time in a few days, and went out there, poked around under the hood, nothing seemed out of the ordinary, then jacked up each side and saw the ungodly amounts of dried dirt chunks everywhere.

I spent a good 20 minutes spraying it at the carwash the day after I hit that mud too, thinking I got it all


There was 2 specific big loose chunks sitting on where the exhaust turns from the passenger side and goes to the drivers side, im almost 100% sure thats what the noise was.

So needless to say, I spent another good 25 minutes laying on my stomach/side with my pressure nozzle spraying the whole undercarriage. Looks new again!

I dont want to start it up and drive it, id like to let it air out a while, but when I got those 2 chunks out, I moved it back about a carlength and didnt hear the noise when I normally would have.

This leads to ANOTHER question. I was spraying the exhaust near the back and noticed some green liquid dripping down, resembling coolant, but IIRC, the Explorer has the Gold coolant. Where the hell would green fluid be coming from that far away from the engine? There were a few drops towards the middle of the vehicle too...

 

[BrianDye]

Update: Drove through town, no rattles anymore! Honestly drives smoother as well, I got so much crud out of everything.

Still very curious as to what the green stuff was though, really looked like coolant, I could even see it in the puddles in my driveway when I left, no distinct smell or oily look though, and didn't come from anywhere near the engine bay which is what confuses me.

Checked all my fluids, everything's full/clean.