I have a 98 F-150 SC 4X4 4.6. It has 118546 mi. At about 115000 it started a tick or clack sound from the right head. The sound would come after I ran on the freeway at 70+ for around 20 min. After exiting and coming to a stop I would hear it. After a few miles of city driving it would quiet down. I changed the oil and added a quart of Lucas oil. It was quiet for a few days then it picked up again. I drained the lucas mix and put in 5W30 Mobil One. Once again it was quiet for a few days, the the tick returned.
I changed all the lash adjusters on that head (also spark plugs at the same time while it was easy). No change. It runs silent at start-up and around town. Get on the freeway for 15 mi and it starts clicking again at all RPM.
Anyone else have this problem? I have seen a few posts that never get to a solution.

 

First off Tallmote, let me welcome you to F150online! This is a wonderful place to give and receive infomation about our beloved trucks. Now, having said that, I have absolutely no Idea what you might have going on. BUT again; welcome!

 

Thanks for the $0.02

 

They make a product called Sea Foam. It is an oil additive that cleans all the parts. I used it on my old ranger and it seemed to work well. My uncle is a ford mechanic and he recommended it to me. He uses it on his van to quiet the lifters. Just something to try, I am not possitive it will work or not on your engine. It is sold at most auto stores, I got it at Napa. Just put it in with the oil about 500 miles before you change your oil. Hope this helps!

 

You could be having an oil pump dying, the pressure is high enough when the oil is cold, and at highway speeds but when the lower speeds are around (getting off the freeway) there is a pressure drop and the valves start ticking. As the oil cools down from being in the city, and driving it thickens up a little. You also could try running a thicker oil. You may be going deeper in the motor than you expected. If you can, try putting a mechanical guage on the motor to read oil pressure. You may be seeing it drop off too much after the oil is hot.
Brian

 

Thanks Wamsleyb,
That is what I hoped would help when I put 10W40 and Lucas Oil. The Lucas is like honey. Very high polymers. That did not seem to help. I am concerned about going to thick on the oil. From what I can see with the cam cover off, the engine does not appear worn. I expected some grunge to have built up after so many miles. The aluminum head is clean enough to eat off. THe rockers still show cross hatch on the cam rollers. The cam lobs have harly any tracks. I was very impressed.
Anyway the oil pressure gauge reads upper half, same as always.
I may try a mechanical guage to verify.
My latest theory is oil foaming. The book says 6 quarts on refill. It will take six and still show a half qt low on the dipstick.
This problem is very frustrating because it makes a nice ride sound like an old POS.

 

It could be a wrist pin starting to go and as the oil heats up it talks more or when it is under load (Hwy rpm's). Just another theory. Also, maybe the oil supply up to that head is restricted so they talk because not enough pressure is there. Maybe that is why it is so clean. Maybe you could try adjusting the lash adjusters to the tighter side of the specs. ?????
Perhaps try the synthetic 5w20 that Ford recommends in their new trucks. They love that stuff, my wifes 00Focus got it at the dealer and it quieted and smoothed the motor a little bit, when it was there for other maintenance. (aka: Recalls)

Brian

 

I have found the problem. There is an oil "restrictor" in each head. This part reduces the diameter of the oil passage feeding from the block to the head. Of course it is at the rear of the head on the right side and makes changing that spark plug look likr childs play. Mine is a romeo engine. Romeos have a ladder frame that joins three cam journal caps. This must be removed to expose the "RESTRICTOR." The damn thing is driven into the head and did not want to come out easily. I was unsure how much force to apply. After an hour of *****footing around, I clamped the vise-grip on it. I was able to twist it free.

The restrictor in this engine is a capped tube about 5/16 in dia. with a very small cross bore at the top. Inside the tube I found a piece of rubber packed against the cap blocking the cross drilled openings. Very little oil was getting past this mess. This *&^$% piece of rubber looks like a cap gasket from some type of bottle or a small (3/4") diaphram. It was mostly intact.

I cannot imagine how it got there or even how it got past the filter.

My technical service manual CD was not very helpful with how to service the "RESTRICTOR". All is said was it is there and is serviceable. I found a great artical on rebuilding the 4.6 at the address below that helped me understand the "RESTICTOR".

http://www.babcox.com/editorial/ar/eb40228.htm

Thanks,
MCM