I have an 02 f-150 supercrew with 5.4 with 117xxx on it it has a knocking sound when it is cold but you can barely here it when warms up factory gauge in dash shows good oil pressure and motor does not use any oil through oil changes.. is it a rod or main bearing or?? any help would be apreciated thanks

 

Have the cats checked. I just diagnosed a '02 F150 Harley 5.4 with a rod knock. Turned out to be a bad catalytic converter. Sounded exactly like a rod knock. My customer took it to the local dealer and they replaced the original cat. It seems the more I read on this the more it turns out that this is a common problem with the Ford cats.

 

what oil and filter are you using ??

 

More to the point of what techrep is asking, what weight oil are you using, I've heard engines start knocking because someone used too thick an oil.

 

Mine has a little bit of a chatter when I start on cold mornings, quickly gone and as smooth and quiet as can be otherwise.

Had a heat shield rust off of one of the cats, so cat issues could explain my mild chatter on cold starts.

 

i will have to check that out it sounds for some reason it is more on the drivers side i didn't know cats could make that sound how do you check them.. thanks for the info.

 

i am running a motorcraft filter with motorcraft 5-20 synthetic blend.

 

Pull the service codes and see if you have any cat errors. Be sure to check for Pending codes also. Crawl under the truck and listen to where the knock is coming from. Take your time. Its very easy to misdiagnose the location. Sound can resonate up the exhaust pipe. My customer's cat had actually popped a weld and would "tick" like a rod knock. I didn't crawl under it like I should have. He took it to the local dealer that found the cause. We had already replaced the drivers side cat a couple years ago and I had told him last year that the passenger's side was starting to throw a "failed cat" error occasionally. I completely forgot about that when I diagnosed his. This appears to be a common "problem" with the 2000+ cats.

Also, when you start it up cold in the morning, is it louder then usual and goes away after about 20 seconds or so? I ask because a rod knock usually gets quieter after about 5 seconds but a cat/exhaust knock takes longer due to heat expansion which is usually slower than oil pressure buildup. Rod knocks tend to get quiet suddenly and exhaust leaks tend to fade away.

 

Just another thought, maybe there bolts lose on the shield covering the torque converter. That can also cause a knock (almost diesel) sound. Fords are also known for this.