f150newbee

Hello everyone, I'm new to the forum, and new to my f150 as well. I was wondering if anyone could offer me some assistance. I love my truck but there's this mirgraine causing metalic rattle coming from around the engine, cats, or tranny. I've explored the possiblity of bad cats but have been told by an exhaust guy, and regular mechanic that they're fine. They've looked, and can't find anything obvious. There are a few previous posters with a similar problem, but no replies yet, and here's a discription. It's a tin like rattle that's amplified when I drive by an concrete structure(sound bouncing off). It can occur between 1500 and 3000 rpm (underload). It is especially obvious on uphills (I guess because of the load). I don't notice any significant lack of power. I've checked all the pulleys on the engine and can't find anything obvious (mind you, I'm not totally sure how to check for faulty bearings other than by spinning them). It's certainly not my muffler, cause' that's been changed (Flowmaster). And a rubber mallets' been taken to just about everything in the undercarriage. Could this be an internal/bearing problem? Or maybe my Cam chain and slack adjuster(if there are any)? Thank you for any replies. Cheers

Fast Hampster

Welcome to the forum! What frequency does this sound have? Does it change depedning on RPM or speed? What engine do you have and what is your truck year? This info is needed for other guys smarter then me to provide you more help.

Good old Bill

Ham asked the questions needed. As far as internal engine noises, I doubt driving along side a structure would amplify those horrible, deep and ugly sounds. Are we sure its not an engine pinging noise? With the PCM's on board, not very common in today's trucks. Thats assuming no CEL is on. Continue looking at the exhaust and any heat deflectors on it. One last wild thought. AC fan, thinking something hitting fan in plenum chamber. Leaf or piece of paper.

f150newbee

Thank you both for replying, and thanks for pointing that out. It's a 2004 4.6L (SC chasis w/4x4 pwrtrain). No check engine light. Not exactly sure of frequency(but high and erratic). Noise seems to occur with rpm, rather than speed. Btween 1500 and 3000, and at any speed. Noise is too loud outside of vehicle to be leaf or other object in AC fan plenum, so loud that can be heard from other vehicles and is equally annoying from other vehcile. It does get a little louder with increase rpm but not much, same for frequency. Thought it was ping, but changed to higher octane, and no change even after about 80kliks of driving, cleaned MAS, and changed airfilter. Not likely to be any heat deflectors, with exception of those around cats, most sheilds are made of soft-aluminum,insulated sheets that make no noise when tapped with metal tool. sheilds on cats are secured very tightly and exhaust guy has gone over all sheilds. Another thing, they had it up on drive-on hoist, put in gear, emergencu brake on, and attempted to simulate, but made no noise. Any new thoughts? Thanks again

transmaster

Is there anyway you can record and post the sound on Youtube. This would help those of us who have driven cars and trucks in such a condition you never want to drive any farther then you are willing to walk back, we have collectively heard just about every sound a vehicle can make.

SouthrnmudslngR

I currently have a similar issue. Sounds like metal kind of pinging/rattling. Mine isn't too loud but increases with RPM too and is high pitch in frequency. I know the rubber thing that goes in the firewall is missing on my truck and thats when I started to be able to hear that noise on my truck.

skidmarks

i have the same problem soulds like and exhaust leak , headers, sounds like exhaust a laeak and metal . i was told it was piston slap or injectors? not sure i have headers and magna flow system with stock cats i want to change them to high flows curious. was told they opened up the lil power more in the mid rpms.

f1502wd1217

i think i might have the same problem i have the 4.6 2wd.Guys if its the same as mind it sounds like when an older 80s model is off timing and if im thinkin right its the distributor makin the noise i might be mistaken and way off but i had an 85 chevrolet that did the same thing as my 05 f150 just throwin a thought out there

Good old Bill

Still like the leaf in the fan, but lets think bigger. Check to see if the engine fan is hitting or rubbing on the fan shroud. Look for signs of rubbing. My thought is a broken left side motor mount and as the engine torques, it lifts up and the fan strikes the shroud.

f150newbee

I'll look into these. But remember, the sound is very metallic, like spraypaint cans being shaken violently. Plastic fan against plastic shroud doesn't seem likely. But it won't hurt to look into it. Thanks. Not sure how to adjust timing though, these newer f150s don't have distributors, ignition modules instead. Interestingly enough, I have given thought to posting an actual audio recording of sound. That may take some time though. Thanks all I'll get on these leads.