A friend gave me her Durango after the transmission crapped out on top of a list of other issues. I have fixed almost everything but I can't find the source of the engine tick. It is loudest when the engine is cold and becomes harder to hear during idling after it has warmed up. However, it is very audible as soon as I accelerate, but there is no noise when I take my foot off the gas. I listened to the engine with a stethescope. The ticking was most audible from the bottom of the central two channels on the air intake manifold. Before I listened with a stethescope I assumed it was a noisy lifter. I tried 5oz of seafoam in the crankcase and drove it 400 miles. Nothing. I replaced all the drivers side lifters and I did find one that had alot of play without even spring pressure and was going bad. I assumed I had found the issue and put it back together (yes, I bathed the lifters in oil over night. I even oiled the cam assembly with lucas before putting the valve cover back on). The noise is still there, unchaged. I want to specify that when I listen with the stethescope, the tick is only audible on the two central channels of the intake manifold on the drivers side. I can not hear the tick anywhere else on the engine. It almost sounds like it could be coming from the outside of the engine when standing near it, but it can be heard very clearly when probing the intake manifold.
If anyone out there has a better intuition as to what it could be based off of the symptoms, please let me know. Thanks.

 

Thanks for the input guys.