knocking 5.4 not piston slap
 

I have a 2000 5.4 with 160k mi. i bought the truck with 113k and the noise has been the same since i bought it. I run the 820s filter with valvoline 5w-30 oil. this is not a dry startup problem either. it does not go away when hot but it get quiter. you only notice the noise at idle or low rpm, never going down the highway or under load. i have read a lot of knocking posts and have not found one with the same problem, any ideas?

I was wondering if you have the same noise as I do.I found this video on Youtube,it is exactly the same noise as mine has.It is quieter when it warms up as well but never goes away.I can't hear it at higher rpm either
Mystery knock of a ford 4.6L - YouTube

You probably are aware of this already...but I'll throw this out there anyway. I think the recommended oil weight is 5w-20.

It could be the infamous exhaust leak...which masquerades itself in many ways...meaning it doesn't always sound the same from truck to truck or engine to engine.

have you done a compression check?

no i have not done a compression check, but the truck gets decent mileage, plenty of power, runs smooth, just doesn't seems like a weak hole. I did change the oil tonite with valvoline max life 5w-20 and a 820s filter. it didn't change anything yet, still the same noise. the noise sounds jsut like the one in the movie. I don't think this is an exhaust leak, but i do have a manifold leaking on one side at the gasket.

I am not a big fan of valvoline. But thats a whole nother story.....


It is probably just a loud injector. You can use a section of tube like a stethoscope and while the engine is running and making the noise listen by the injector.

Consider a good oil like Castrol or Mobil 1. There is a reason High performance engines come out of the factory saying Mobile 1 only, or stock oil at a Lambo or ferrarri dealer is castrol.

Id fix any exhaust leaks....& as suggested^^ try to isolate where this is coming from if still present.

Old school in me says, that sounds like more than just a exhaust leak

I just pulled all the valve lash adjusters in mine.Will be putting new ones in on the weekend,I'll let you know Fordman if it fixes my noise.

Changed all 16 lash adjuster,the rockers,cams and valve springs looked good.....noise still there.

i got my hopes up too soon.

timing chain guides broken?

I had the same noise in my '98 Expedition when I bought it. I thought it was valve noise but it turned out to be #4 and #8 rod bearings were beat to death. The truck drove fine and the noise was minimal. It might have lasted for a few thousand miles or maybe only
50. Parting it out now.

I hope you don't think I'm highjacking your thread 78fordman.
Moto Mel, the bottom end has definitely crossed my mind.It does sound like it at times but I see no other evidence pointing to rod bearings.The hot idle oil pressure is 20 psi and 50 @ 1500 rpm and have seen no brass in the oil at all.I have cut filters apart looking for debris and nothing there.
Just curious Moto Mel if your noise got quieter as the oil warmed?
Not saying you are wrong,I need to get to the cause of this even if it means dropping the oil pan....I'm sure 78fordman is as curious as I am.
Again 78fordman I hope you don't think I'm highjacking your thread.

Mine was pretty quiet even at an idle but definately there, You could barely hear it while driving, even putting a load on it did not make it loud enough to get excited about. Definately not as loud as the Mustang in the video. But I am more than just a little bit of a motorhead and I knew it was there so I searched until I found it. The best tool for this is a mechanic's stethescope and listen to the bottom of the block casting, if it's the con rods you will hear it and money flying out of your wallet. Poor attempt at humor there.
It was spun bearings and the crank was ate up. The bottom shell had slipped to the top of the journal and the top shell and was taking the pressure or impact of the compression while the engine was running and not making the loud pounding noise we normally associate with a bad bearing.

mine is only at 1000rpm and under. While driving down to road or even reved up with no load it is quite. I have no codes but i am going to get a couple of tensioners and guides and see if it is some chain noise.

I have a 2000 f150 5.4 I did mine and the chains were stretched even tho the tensioners were all the way out, chains were slapping, it was a time consuming job, I ran into a lot of snags hope yours goes well