Figured out the Rattle in my Truck

Projects & Restorations

  1. Justwondering

    Justwondering Well-Known Member

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    Apparently, after 285,673 miles, my 2000 Chevy Silverado I got from my Dad has a dying catalytic converter.

    I say 'sounds like rocks on my skid plate'
    He says 'yep, you need to take those rocks off your skid plate'
    Followed by 'or could be on the heat shield'
    This is the same conversation I've had with 4 different guys (shade tree mechanics, oreilly guy, brother, and husband)

    6 attempts at removing rocks for two weeks... and yes, there were 4 inch rocks down to 1 inch rocks and a huge fender washer--very rusted that I pulled off the skid plates

    After 2 weeks, I drove to the place I get my tires that also changes oil.
    I say 'Don -- would you see if there are still rocks on my skid plate?'
    Don says 'sure, just pull it into the first Bay'
    Don says 'you wanna go down in the bay and look at it with me?'
    I say 'Naw ... I'll just let you do the dirty work' ... we laugh

    After checking,
    Don says ' I dont see any rocks. Go ahead and start it'
    I start it.
    Don says 'your catalytic converter is dying or dead'
    I get on the floor and ooch under so he can show me how mucking with the orientation of the catalytic converter makes the rattle go away.
    Not a hanger problem.

    And yes, everybody in the waiting room was staring at us as we are discussing the problem -- me on the floor halfway under the truck and him in the bay on the platform for changing oil.

    Don's a good guy.

    I finally get up and shut off the truck and he comes upstairs to discuss.

    At least I have a direction now.

    Still sounds like a really bad redneck truck at the stoplights but I will get a game plan together.

    JW
     
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  2. slant6billy

    slant6billy Well-Known Member

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    There is an "Offroad" technique fix.... as in not street legal. Something about disconnecting the the exhaust after the cat and using some type of extricating device to pull the tired guts from the cat. Reconnect pipe and go offroading eventually. The ratlin will be gone
     
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  3. Aspen500

    Aspen500 Well-Known Member

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    Using the "extricating method" will also give you a check engine light and a P0420 or P0430 catalyst efficiency below threshold codes. Is it a 5.7L with only one cat or a 5.3L with one for each bank in a y-pipe? What usually happens is the stainless mat between the shell and substrate comes apart and then the substrate rattles around in the shell. Annoying as all hell, isn't it? lol Aftermarket replacement so called "direct fit" converter assy's aren't all that expensive. I put it in quotes because they usually aren't DIRECT fit, but are close fit and need a little tweaking to actually fit but an true exact fit OEM assy from the dealer is going to be $$$$$$$$$$$$$$$$$$$$$ (if even available for a 21 year old truck).

    Funny part is, the original cat on my '96 Dakota started rattling around 60,000 miles and since cats are 8/80 warranty, had it replaced at the dealer. At 65,000 miles that one started rattling so,,,,,,,,,,,the dealer replaced it again. At roughly 70,000 miles guess what? Rattle, rattle, ratlle. Even though it was still under warranty I said "bleep it" and bought a Catco hi-flow direct fit (it was about $100 back in 2003) and put it on. Now at 180,000 miles it's still quiet as can be. :)
     
    Last edited: Oct 27, 2020
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  4. 80mirada

    80mirada Well-Known Member

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    I replaced the right side cat on my Charger, with a direct fit. Fit pretty well, if I hadn't mangled the joint in the original pipe it would be near perfect.
     
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  5. MiradaMegacab

    MiradaMegacab Well-Known Member

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  6. Justwondering

    Justwondering Well-Known Member

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    Aspen500 must have sent me his rain clouds... been raining and highs at 45 for 3 days.
    What the heck... supposed to be in the 60s and right now. Sheeeesh

    I've had the offers of
    1. 'I could cut out that cat and weld in a straight pipe -- just don't take it to Dallas to be inspected'

    2. 'You would have to buy a new cat but get a good one not a crap one' with absolutely no context on what is good or bad (you folks gave me more info here)

    3. 'Just take the guts out of the cat and weld it back in place'

    4. 'Use this as a chance to learn tig welding and cut it out and put another in its place ... just a shame you don't have a lift. it would be easier to work on.'

    5. 'Why are you driving that old truck, just get another newer one' (I drive it cause it reminds me of my dad AND it has a seat warmer which makes me smile when I turn it on cause Dad was so pissed off when he realized his replacement truck didn't have a seat warmer. I sooooo enjoyed calling him on cold mornings to tell him how much I loved that seat warmer -- shame he no longer had one... lol)

    Megacab -- love the video. Two reasons: 1. gives me another option and 2. someone working in tight quarters where you can only move the ratchet 1/4 turn at a time... just like me. ;)

    JW
     
  7. Lightning II

    Lightning II Well-Known Member

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    On the cats: anything labeled “high-flow” essentially. They’re around $150~ at Summit.
     
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  8. Aspen500

    Aspen500 Well-Known Member

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    Sorry about the rain and below normal temps!

    We're booked through next week already but if you can come the following week, we'll fix you right up at the shop. It's only 1,200 miles each way :D
     
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  9. Justwondering

    Justwondering Well-Known Member

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    :)
    JW
     
  10. 1982 IMP

    1982 IMP Member

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    I have an 03 silverado with a 5.3.I put a Pace Setter high flow front pipe with cats.Fit perfectly and works well.Been on my truck for a year and a half.
     
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  11. Aspen500

    Aspen500 Well-Known Member

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    Well, I had to open my big mouth, bragging how the CatCo hi-flow cat on my '96 Dakota was still good after being in there for 100,000 miles..............A couple weeks ago it started to rattle. Figured I'd get to it eventually. Then yesterday coming home from work, I turned the corner onto a highway, stepped on it and,,,,,,,,,,,,,hissssssssssss and what felt like about 50 hp so eventually became this morning and I nursed it down to work and sure enough, the rear honeycomb in the cat came loose and turned sideways, blocking 80% of the outlet pipe. It now has a cat delete pipe, at least for the time being. Funny thing is, it's a '96 Dakota and of course, has OBD-II but it was built 08.15.95 and has no evaporative emissions monitor or catalyst efficiency monitor yet it has a downstream cat monitor O2 sensor which does absolutely nothing. On a scanner it shows as a straight line and 0 volts (discovered that many years ago). The sensor is there, the wiring is there, the PCM ignores it. Also has all the evap monitor wiring that plugs into nothing. Unlike JW's Silverado, the Dakota won't have a check engine light on without a cat. I may replace the cat at some point though,,,,,,,,,,,,MAYBE.;)
     
  12. Justwondering

    Justwondering Well-Known Member

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    Curses...
    Just like Aspen says, my check engine light is on and my catalytic converter is rattling like its full of rocks.
    Its scheduled for repair in January...later in the month.
    JW
     
  13. 69-

    69- Member

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    So glad my LeBaron has the cat delete option, as it is n europe export car...

    Sry. :cool:
     
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