Ok, so I've ready tons of threads about the dreaded "ticking" noise, which my truck definitely has. I've always thought that I had the cam phaser issue, but now I'm thinking it's an exhaust manifold leak. Reason being, is that it is much worse (sound wise) on a cold start up and under acceleration while the engine is fairly cold. After a cold start and the engine returns to normal idle rpm's, the noise almost goes away until I give it some gas. After driving it for a little while, you don't hear it as much under acceleration.

Now for my questions, which I really haven't seen discussed in any other threads. Lets say I do have one, or both, exhaust manifolds leaking. What kind of damage could become of this if it goes un-repaired? How long could I go with a leak before it starts to do further damage to the motor? What would your replacement method be, new exhaust manifolds or switching to headers?

Thanks in advance!

 

If not addressed you may eventually burn up the exhaust valves and seats. Could even be looking at CAT issues too, I suppose. Obviously long-tubes are the kick-*** way to go and improve the powerband a little on these trucks. That being said, $500-$600 for a new set of headers ($1400 for the Dynatechs with CATs already welded-on) ... is a "little" more than some junkyard exhaust manifolds.

 

Mine does the same thing...I've not gotten in too deep to see where it's leaking yet. Mine sounds like it's the passenger side, but I can't tell if it's the manifold or the pipe close to it.

 

hi, there shouldnt be any major effects besides the compression exhaust variable, because its not going to be what it should and you might lose some performance, not that noticable unless revving high and low in the highway, but the licking has nothing to do with that, the ticking is when the engine is cold the lifters are not fully lubes with oil so it ticks, and if it ticks after your engine is in operating temp then your lifters are worn and they are stressing too much, which the cams and lifters are not rubbing/sliding in cycles but "hitting each other" because they are worn and you may hit the pistons with dropping valves, leading to major repairs, but usually its just your valve stems need replace.

 

There is an off chance that its your manifold. More than likely what your experiencing are bad valve lash adjusters and probably a couple of bad followers. I had been struggling with this ft over a year until I replaced them and that is what finally silenced my engine. Also for whatever reason the ticking seems to always be more audible on the passenger side. Too verify find a pipe or better yet an automotive stethoscope and hold it up to valve cover, the noise will be very apparent. The bad adjusters will also sometimes cause the start up rattle that many associate with the chain tensioners. For a video of the part with the problem checkout my thread concerning valve lash adjuster ticking.

 

I had the same issue it turned out to be the passenger exhaust manifold. I confirmed it one day when I was driving on frontage road with a sound barrier wall to my right. I opened the passenger window and hit the gas you could hear the exhaust leak plain as day. 600.00 fix at the dealership.

 

When I redid my exhaust with headers, the mechanic showed me my old exhaust manifolds. I had ticking as well and figured it was always the phasers. Well, when we flipped the manifolds over, he was telling me that most of the 5.4 offroad users usually develop a small crack in between the folds next to the mounting holes. He also had a couple of pairs on hand that he pulled off border patrol and fire units, and they pretty much developed in the same area. It was pretty weird.
Anyhoo, headers are tough to justify. I have longtube pacesetters on mine, and I can notice some good response changes and acceleration, but youll definitely have to get a custom tune from PHP to have the full potential unlocked. If you do pull some used manifolds, make sure you get some good gaskets too.