Hello everyone! have a 2001 4x4 Lariat with 5.4 and 75000 miles.
have this persistant bit of a knock thats from right side and is louder when idling in park. crawled under with a stethoscope with engine running a listened at different areas and the knock is more pronounced right at the catalatyc convertor. could this be the culprit?

 

Spark plugs make a ticking sound just before they blow out of the head. I thought mine was the cat...but it wasn't

 

Could very well be the cat. I had the same issue on a Lightning a couple years back. It was the 'brick' coming apart inside the cat.

 

I am experiencing the EXACT same thing, only the sound is coming from my driver's side cat. I used a small metal tube to isolate the sound. I'm taking it to the Ford dealer tomorrow, so hopefully I'll know then what it is. I sure hope it's nothing worse than a bad cat.

 

maybe.

Ed

 

I have not had this problem myself. If this is coming from the light-off converter as descript in the TSB, I would say the engine is running rich. The first thing I would try is disconnect the battery for 15 minutes. It doesn't cost you anything to try it. If the front O2 sensor haven't been changed, the second thing I would try is to replace them. The front catalytic converter is use to burn off un-burnt fuel. Which I believe is a waste of our money on today’s cars and trucks. We pay out the a$$ for people in DC who think they know it all. But that's a hold different story.

Just for the record. Did you know that the catalytic converter produces NOS Nitric oxide which is more harmful to the environment than Carbon monoxide? But we big motor guys are the ones who don’t care about the environment right? LOL

 

I bet it's the PCV valve echoing thru the head into the exhaust chambers on that side. A Motorcraft valve won't do that, but a Fram valve can get very noisy and sound just like a rod knock lol. Not kidding, I would make sure I had a Motorcraft valve in there first before going any further - there cheap anyway.

If alls well with the PCV valve, I'm think it's what DrTriton found to be the problem in his experience - a brick breaking up inside the converter.

Personally, I had to install 7 or 8" band clamps (2 per side) on the heat shields when they got noisy. But the noise was more of a chirping sound @ idle - more pronounced when in "D" w/foot on the brake. Heres a diagram from a Ford TSB of how to wrap the rear converters if that's the problem, it's probably from the same TSB F150PARTSGUY posted. It's the diagram that came attached to the 98 F150 bulletin. -



Good Luck.

 

I stopped by the local Ford dealership today unannounced, and they managed to fit me in for a quick look. They are stumped, and asked that I drop it off Monday morning before work so that they can fully inspect it then. I'll be sure to notify them of the above TSB and the PCV guess.

I'll let you guys know what I find out.

 

Gr8 ! I'm curious what it is. I've only heard the PCV do that myself. Yea , what ever it is please post.

 

Yes be sure to post fix. If you can find out from the mechanic how he/she deteremnd the difference. That will be as helpfull as knowing what the fix was..

wats up brew?

 

What I find hilarious is that the TSB mentions the sound being noticeable at drive-up windows, and that's the EXACT same thing I said in my thread here on this forum with the same complaint. And that was before I'd ever seen the TSB!

The TSB fits my complaint to a "T". Mine has the same sound as a connecting rod knock, only the knock is inside of the catalytic converter. Also, mine is on the driver's side, while the original thread starter (lockheed) says that his is on the passenger's side.

Hopefully I'll know tomorrow (Monday) night what mine is. I've read that the wrap kit mentioned in the TSB is $500!!! If my problem turns out to be what the TSB states ("normal"), I'd almost live with the sound and keep the $500.

 

Mine was $8 and took less then 10 minutes ti install - You should have said drive- thru window noise before - That's cat churp and easily fixed. I have posted the fix yesteray above . Not sure where an the hell , you came up w/$500.

 

My sound is not a loose heat shield or PCV valve. Mine isn't a rattle -- it sounds just like a connecting rod knock, only it isn't coming from the engine itself, but rather from INSIDE the driver's side cat. The dealership also told me that the "brick" inside the cat is intact, and not broken apart. If you were to use a stethoscope, you would only hear it at the cat. It isn't heard at the engine block, and it also isn't heard while standing in front of the truck above the engine. The $500 quote came from someone talking about the wrap part number 4L3Z-5E258-AC referenced in the above TSB.

I really wish that it were as simple a fix as the one you mentioned.

 

Not much Tumba -

Sounds like this dude might need a motor after all For $500 you could buy a whole exhaust system - both sides in front of the Y. I 'm curious to see what the dealerships going to try to fix.

 

They probably won't "fix" anything. They'll probably chalk it up to the TSB and call it "normal" and instead of curing it, they'll mask the sound with a sound-deadening wrap to appease me.

From their initial inspection yesterday, the dealership said that they'd pretty much ruled out bearing noise (rod/main). They also agreed that the sound is "coming" from the cat, and not the transmission or engine oil pan.

If it turns out to be a rod knocking (or something similar), I'll keep driving the thing until it quits. It runs just fine, has plenty of power, and holds good oil pressure. I definitely don't have thousands of dollars for a rebuild at this time.