This weekend I pulled the exhaust manifold off and checked it, and everything looked good. There were no signs of leaking or cracks.

I did find out that the plug wire that goes to the cylinder making the noise was broken. I realized this when I was going to remove the spark plug to check it and the connector from the plug wire was still attached to it! I don't think this is what's causing the problem, because I am not sure when it broke. It may have happend when I was pulling the plug wire off the other day. But, you never know!

If this thing does happen to turn out to be a rod bearing, can I get by with changing the one set of bearings on the rod that is making the noise? Or do you have to change them all?

I was listening to the engine as it was warming up, and I noticed a slight tick as the temperature gauge got about a 1/4" beyond the cold mark. When I heard the tick I started revving the engine and you could hear the noise starting at 1800 rpm. You can't hear the noise at all until it reaches that point on the temperature gauge though.

I have finally figured out how to upload a video to You Tube. Please overlook the beginning of the video! If you listen closely you should be able to hear what I am talking about.

http://www.youtube.com/watch?v=ArmGelJgvYE

 

bump!!

 

Sorry, dude, I couldn't hear any knocking or ticking in your video. Did you check the valve springs and rockers on your #5 yet? Also, if that spark plug wire was broken, it will make a ticking sound every time the spark jumps.

 

I did a second video: http://www.youtube.com/watch?v=NFF8BQPl9UY

I haven't had a chance to pull the valve cover yet, but that is definitely next on the list. It is harder to hear on the videos but on the second video if you listen near the end you can hear the rattle. It sounds like something is broke inside of the engine rattling around. Maybe when I pull the valve cover I will find something. If not, I am going to pull the oil pan again and check the #5 bearing a little closer.

I switched the broken wire to #7 and the good wire back to #5 (my new set of wires hasn't came in yet) and it made no difference in the rattle.

 

Sounds like a lot more than a tick, at least at the end of the second video.

 

I agree with you there! It is definitley more than a tick. I can feel a hole burning in my wallet.

 

I heard it the second time. It's not a knock or a tick, but a definite rattle. It sounds like something exhaust- or flexplate/TC related to me.

 

The main thing that concerns me is when you pull the #5 plug wire and it goes away. That eliminates the flexplate/TC. I won't have time to work on it this weekend, but as soon as figure out something I will post.

 

bump!!

 

I have had the truck looked at by different people and everyone is saying the piston is rattleing around. The only problem I have with the diagnosis is the rattle only starts after the truck warms up. Usually a loose piston will get quieter as the engine warms up. This is doing the opposite. I added STP to the oil and it quitened the rattle down a little. This seems more like a rod bearing to me. I guess I need to drop the pan again and take the cap off the connecting rod and check it again.

I have also took the valve cover off and check the rods, springs and rocker arms. Everything was fine. I have checked for exhaust leak (took the manifold off and inspected it closely). I checked the torque convertor bolts and everything is okay. I pulled the serp belt off and ran the engine and the rattle is still there. I guess that pretty much points to either the piston or connecting rod bearings.