JackalAR

2001 F150 with a 4.6L PI Romeo in it. 107k mi. Been hearing some ticking under the hood for a while now, but dismissed as old injectors getting loud on me, but it got bad enough that I looked into it and it is much more pronounced on the rear driver's side. This made me think possibly a failed Ford Racing header gasket but I see no signs of failure and I have ruled it out. Now I am thinking it is one of the two rearward driver's side HLAs going bad on me, but here's the thing, the ticking sound seems to travel down through the exhaust as well. I have stainless long tubes and it is really pronounced down at the header collector flange. I just had the exhaust valves faced 25k ago. I'm hoping it is just the HLAs because it looks like I just need $150 set of new ones and a $70 tool, but is it normal for the ticking to come through the exhaust like that? Thanks!

VIDEO:
http://vid493.photobucket.com/albums...psvghkanph.mp4

JackalAR

UPDATE:

Turns out 2k mi. into my last oil change and I'm 1 qt. low. I added a qt. and 5 oz. Seafoam and let it run for about 15 min. and the ticking is only about half as loud or less so this helps solidify an HLA issue for me. I took a long screwdriver to each exhaust tube and it sounds like the rear most cylinder is where the issue is. I'm dreading working in that tight space again, I can only imagine how bad it is for your guys with the Mustangs, except for the height situation. I usually work from inside the engine compartment between the radiator and timing cover since I have e-fans.

Any input appreciated.