My 2003 F-350(5.4) just turned 80000 not long ago, and ever since it's been getting colder(november and so forth) my exhaust has been rattling after the truck has warmed up. The colder the weather, the worse the rattle, and before, it used to only rattle when it hit fourth and the rpms settled down, but unfortunately it's starting to do it more and more. At first I thought it was a mounting or design issue with my cat-back, but my mechanic says it's the heat shields on the cat and the manifolds. I dropped it off and he couldn't find where it's coming from. He actually said that super duty modulars are known for doing that. Any similar experiences, or suggestions?
I find myself having an unusually heavy foot just to avoid this low rpm rattle,(lower rpm, more vibration?) and it's annoying the hell out of me.
The sound could also be the transmission inspection plate. At the front of the tranny where the engine and transmission meet there is a thin sheetmetal inspection cover. This plate has be known to rattle and make an annoying noise.
My dad had a noise on his 03' F-250 and I narrowed it down to the inspection plate. I fabbed a new plate out of 1/8" Aluminum using the stock plate as a template. No more noise. This plate is a common problem and at least on my dads truck was in the lower rpm range.
Two bolts hold the cover on. I suggest removing the cover and taking the truck for a drive to see if the sound goes away.
My 04' F-250 has yet to have a problem yet.
The heat shields on the y-pipe are welded on good so I doubt they are the source. I'd go under the truck if you can and take a look but I would look at the inspection cover first.
I have a 2000 f-250 SD with 5.4 - my inspection plate seems to be sandwiched between the trans and engine----I had a kind of scraping noise that was driving me crazy...undid the bolts from inspection plate and bent it out a bit - left out bolts -no more problem----couldnt have been scraping but maybe harmonics or some other crazy thing was causing noise....
you might be shifting too low an rpm....bad for engine bearings to lug the engine for gas mileage sake...
it actually turned out to be the heat shield around the large cat prior to the muffler, it consists of two pieces (top and bottom) crimped together on the sides. I'm really considering removing this rattling demon from my setup, because it's driving me crazy. Could I damage anything with the extra heat or would my cab get hot (i'ts directly underneath it)???
I usually turn my mig welder way down and put several tack welds on them, we used to take them off and never had any problems, but then we attended a catalytic converter seminar and they said don't take them off on the slight chance the vehicle starts on fire we would get the blame, so now we just tack them back on
I was concerned about heat, but setting a fire, wow; I mean if I were to replace the cat for a high flow unit would that mean I would have to have a heat shield fabricated for it???
I haven't heard of any of the newer vehicles catching on fire because of a converter missing it's shields, but when a converter gets clogged they glow cherry red and I would imagine if the circumstances were right it could start a fire. Years ago when they had the big pancake style cat conv. an inch under the floorboards, the converter would clog and light the rug on fire, scare the hell out of the driver, they would pull over and try to find something to put the fire out (sand, water whatever). If you were to buy a high flow cat, it should already have heat shields on it. But I wouldn't change the cat because of a heat shield, if it's clogged then change it. There are milllions of people driving around without their shields on, some fall off without the owner even knowing. We have to weld them on because of the "since you was the last one to touch it rule" I didn't mean to scare you into thinking your car would burst into flames.
Last edited by flowriteexhaust : 01-26-2008 at 08:43 AM.
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