View Full Version : F-150 Exhaust
09-10-2007, 09:26 AM
I got true duals put on my 2002 F-150 with a 5.4 about a month ago, I noticed after driving a awhile the right pipe has a odd putting sound. It has a fairly consistant beat, and at cold startup or after an hour on the highway it isn't there, mainly after driving around town for awhile. The guys at the exhaust shop think it might be the rear cat, which I find unlikely with only 49k on a truck that runs perfect with no check engine light. If it is the cat I told them Ford would get to look at it first for warrenty which they didn't like, they started spouting off about how the exhaust is now altered and the warrenty is now void (it shouldn't be). If I had to do over I would probably go to a different shop, and I will when it is time to dual my Ranger.
I had them put on 2.25" duals after the stock cats with Thrush glasspacks, it sounds great from in the cab as you can't hear the strange noise from there. Any ideas what would do this?
09-11-2007, 10:16 AM
Would too much exhaust pipe sealer cause this kind of a noise? I am very tempted to pull the pipe right after the cat out and see if I can see anything in there, whether it be something loose in the cat, extra sealer or whatever. It honestly does sound like something in the pipe when it makes the noise. I have been reading/asking around about the cat, they don't just go bad. The insides are like a ceramic material and stay that way pretty much until they get exposed to raw fuel and melt down, which doesn't really jive with my trucks symtems.
Is the sealer going to make it a pain to get the pipe off for an exploratory, and if so does anyone have any pointers for dealing with it?
09-11-2007, 09:46 PM
a real exhaust shop would have welded the pipe...not done something as ghetto as pipe seal it. even if they did use such a compound, it usually dries to a hard crust (then flakes off, then leaks), so i dont really see it making a noise like that.
cat converters rarely fail....especially at that low of mileage. as you've learned, they use a coated ceramic substrate which is fairly durable but can fail in two ways. first is heat, like you said. second is physical shock...aka hitting the cat or nearby exhaust on/with something. this can cause the substrate to break loose and plug the converter.
checking your vacuum would likely tell you if you have some kind of plug in the exhaust system.
i'd be more apt to believe theres a leaky valve or engine misfire of some kind.
09-11-2007, 10:35 PM
I prefered to have it clamped at least in a couple places incase I ever had to work on it so I wouldn't have 2 20' long pipes to wrestle around, if it does give me a problem I can weld it myself easy enough. There is only 3 junctions per side that are clamped, after the cats and before and after the mufflers, the tips if they even count are welded. The closest thing that sounds like it is those plastic pinwheels when you are a kid, it sounds like them when you blow really hard into them, but slower to match RPM.
I can't see the cats going out early either unless they had help at the shop, which I also doubt, my dad's tractor shop and the exhaust/tire shop trade alot of business back and forth. My brother goes back to his dealer from Co-Op in 2 weeks so I might have it checked out when he gets back for a miss and readings on the cat. I looked at the cat closer tonight and it doesn't look like it has gotten hot, I smacked it around a little and it didn't rattle, those are the only tests I know of without the fancy computer stuff. If I didn't have the coil over plug crap I would zip them out for an inspection too, but that is slightly a pain. And like the cats the plugs should still have some miles on them as well.
The truck drives great, I drop the hammer and it gets going without blinking warm or cold, still gets upper teens on the highway like always. The only thing that bothers me about the noise is the possibility it is something that might grow into something bigger.
09-12-2007, 12:04 AM
I prefered to have it clamped at least in a couple places incase I ever had to work on it so I wouldn't have 2 20' long pipes to wrestle around
09-12-2007, 08:36 AM
That is pretty much how mine is aside from being clamped with the factory style clamps at the same place as you passenger side is clamped and where your driverside pipe welded. From there it is a solid pipe back to the mufflers, then a solid pipe to the tips for both sides, wish I had a camera. They actually have a pretty good rep for their exhausts.
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