I searched the threads for information on why the 5.4L has the engine knock and diesel sound and found several pieces of information, but I have a new question.

My local Ford dealership acknowledged the problem and that while it is annoying, it's not something that needs to be fixed. In fact, the service center recommended that I use 4 quarts of 40W and 2 quarts of 50W on my next oil change and that the noise problem would completely go away!

Any one have thoughts on this? I'd hate to use heavy weight oil and cause problems with the engine but since they made the recommendation, I'm considering doing it.

Thanks for the help and sorry this is so long.

 

I have always replace a quart of oil with a quart of lucas when i change mine. it has always taken away the knocking.
latley i have been using 5w30 and its been going good as well.

 

Sounds like a plan; I think I'll give it a shot (fingers crossed).

Thanks!

 

40W and 50W in Ga!? Wow that's heavy. I'm in Phoenix, Az. and always use 5/25. Thought I was losing my mind until I read this. I have an '06 that I occasionally "think" I'm hearing a knock. I'll swap out a qt of heavier oil next oil change. Let me know how it works out!

 

I used a synthetic blend last change that's a little quieter, but not much. I have an 07 though.