4.7L V8 magnum

Engine sounds like it's ticking/knocking. It almost sounds like it's coming from the alternator or right behind it. I'd like to think it's something like an accessory component or a bad pulley or belt but it sounds real bad. All fluids are where they should be. No noticeable power loss. Noise gets louder when accelerating and sounds like a ticking/rattling noise. Oil pressure and temp gauges are normal.

Helpful info:

Truck is hot wired (bought it with no key)
When starting the truck last night my negative terminal started sparking and then my headlights went out and won't come on.

The steering column is completely exposed and I took the rod out of the back of the ignition to turn and unlock the steering.
The truck died twice at stop signs on the 20 minute drive home.

Video of the noises: https://youtu.be/PbMhNqoyHPw

Any insight is appreciated. I don't even know where to begin troubleshooting.

 

It's hard to tell from the video.

Take the belt off and run it, just for a minute. That'll disable all the accessories to rule them out.

The pitch doesn't sound right for a rod. How many miles are on this? Timing chain tensioner maybe?

If there is good news for you, on the headlights, they do not run through the CTM. Power goes through the PDC under the hood, fuses G and B then to the headlights. The grounds are switched not the feed. They run through the multifunction switch to the headlight switch and then to ground, G200, LH side of the dash on the arm where the dash pivots.

Try the "pass to flash" feature too. That bypasses the headlight switch - but it uses the same ground.

 

Thanks for the reply. Im going to go ahead and take your advice and pop the belt off. When I started it up for my friend to listen he mentioned it sounded like a lifter tapping. Does this sound like a reasonable diagnosis based on my problems? The ticking is horrible at higher rpms and still very noticeable at idle.

 

Update: pulled serpentine belt and started the truck. There's no difference whatsoever. After hearing it this time, I think it's coming from near the valve cover. I was hoping someone could point me in the right direction as to what to do next as I don't have a lot of experience when it comes to engines.

 

At first I thought rod knock, but it sounded lighter than that when you pressed the gas. Use a long screwdriver up to your ear and touch the engine where you think it's coming from... sort of a cheap mechanic's stethoscope.

 

The lifters on the 4.7 will get noisy with age especially if you use cheap oil in the engine most of its life. Changing to quality oil will not help at this age the wear has already happened its not terribly bad just noisy. I do recommend a quality oil though but it will not reduce the noise only replacing the lifters will help and may be good insurance that you don't toss a lifter arm as it does happen in these engines. Part of what happens is the lifters get dirty from the low quality oil used they get sticky and pop up just a fraction slower as they age thus the ticking.


You could try a good cleaning oil for a year or less this may clean the lifters and reduce the noise some then go with a high quality oil next oil change.


Note the 4.7 should get regular constant oil changes if not the lifters will get dirty/sticky

04 Jeep 4.7 rocker arms falling off..DIY repair - YouTube

 

Pull the valve covers. Maybe there is a lifter or rocker arm problem.

It's not unheard of for the 4.7 to throw a rocker arm.

Does it seem to be running on all cylinders?

 

I have had the same sound and if its coming from a vavle cover then it could be a broken vavle I have had it happen before and again today I thing I blew another one. with mine It gets louder when I go to drive it and has major power loss. if that's the same as yours I would think that could be the problem