kristy.schiller

Hi all. My 1999 F150 4.2 ltr sounds like a broken garbage disposal. I have checked around and believe the sound is coming from the exhaust - passenger side under the cab. What is that "box". I have to exhaust pipes run to this "box" and exit as one down to the muffler. Any idea what it is and so I don't get taken, about how much it will cost to repair? I try to do the "easy" stuff myself, but this looks like you need a torch and welding experience - I am not up for that!

 

I doubt it's your exhaust if there is a grinding. First, the "box" is a catalytic converter. This is an anti-pollution device (some claim) and they are very expensive. Your starter and flywheel are in the same area. I'm guessin' you have a broken tooth rattling around in there (in the bell housing). Crawl underneith and look for a sheet metal guard at the bottom of your bell housing (where your flywheel is). Remove the plate and feel along the shelf for a metal chip. This should be where your tranny meets the engine, at the bottom. Also make sure your starter is seated correctly. I worked on my neighbor's kid's truck (though he thought it was a bad selenoid since he just got a 'thunk' noise when he tried to start it). Turned out the ground wire was on the mating side of the starter rather than on the outside of a bolt. The wire acted like a shim. That can cause teeth to break/wear on the starter or the flywheel. Hope this is the cause. Good luck!

 

when you hit the gas does the sound get worse, and as the RPMs go down the sound goes down some? is it kinda a poping sound? when is the noise the worst or is it always metal grinding? the more info you give the easer it will be for us to figure out what is cuasing this noise,

 

Thanks guys!

It is my cat. Since I bought my truck in California a few years ago, it's even more expensive - well you know BigTruck311. And by the way - you're truck makes my truck look like a baby!
Anyway, the $700 part is on order. I am glad I found this site in my quest to not get ripped off. I'll be back next time something goes wrong.

 

wow 700$ get a aftermarket cat for like 100$ go to www.troyerperformance.com it is a way better cat and alot less expensive, dont go to the dealer for that stuff order it and have a muffler shop do it if you have any Q' i got a few good sites to check out to get one way cheaper and it will be better too

 

What was grinding, did they say? Maybe it's just a heat shield rattling?

 

How does a part with no moving parts in it at all have a grindind sound? Something doesnt sound too right there. Either your hearing a vibration noise instead of a grinding noise, or someone is taking advantage of you. $700 is way too much for a catalytic converter.

 

Alrighty then!

It is the cat. I actually diagnosed it first and nobody beleived me because I am a chick. Three guys took a look at it and it is the cat. Something broke loose inside of it and is rattling-the more exauhst through it, the louder it is. And when the truck is off you can hear it if you bang on it. But I am at a loss now. I needed one of you to come to the shop with me! I actually called my mechanic back home in Long Beach, CA and he said it does have to have the OBD2 sensor, not just the O2 because my truck's computer chip is set to California emissions. I don't think he'd lie because he had nothing to gain. His price was 850 And the OEM is 1200 just for the part. 700 is an after market-and had the OBD2. I guess I am a wimp I'm afraid to get something that may make my truck run rough and set off all the dash board lights-could end up costing me more later. Right now he is running perfect-and this will be my first non-routine-maitenence repair and he has 117k miles

 

It's not that no one believed you. A rattle is one thing. Grinding is another. Rattling is plausable for a cat--not to mention everything from the manifold to the tail pipe. Grinding is not. When I think of grinding, I think of two metal parts rubbing with force, not just something bouncing around.