1998 Sub. engine noise

Discussion in 'GM Powertrain' started by CLMonti, Dec 12, 2008.

  1. CLMonti

    CLMonti New Member

    I have a 1998 Chevy Sub. 1500 4x4 that makes a loud tapping noise after it runs for several mins. It has 150k miles and we are the original owner. After the engine is warm, and tapping, there is a noticable lack of power. There is also a sound very similar to a whistling or whine coming from the area near the passenger's side firewall. Could this be an indication that one of the catalytic converters is bad? It runs fine until the engine is up to temp.
  2. vncj96

    vncj96 Epic Member 5+ Years 1000 Posts

    First off does the whistle go up and down with the speed of the vehicle or the speed of the engine. What kind of tapping? again with the engine speed or vehicles speed. do you hear these in side the truck while driving or while its sitting idling
  3. ct9a

    ct9a Epic Member 5+ Years 1000 Posts

    Welcome to the forum! As vncj96 said, get us some more details and I'm sure someone here can give you a hand.
  4. JMoney02

    JMoney02 Epic Member 5+ Years 500 Posts

    Do really need more info, but sounds as though you have spun a bearing. Does the tap come from the top or bottom of the motor? Top would be lifter/cam, bottom would be a bearing connecting rod, which
    will cause a major loss of power, especially for the miles. So post some more info and we can go from there..

    Last edited: Jan 2, 2009
  5. CLMonti

    CLMonti New Member

    The noise is coming from the bottom of the engine. The whistle does increase with increased RPMs. It also has a rough idel when it get to temp, but not to the point that where the RPMs jump all over.

    I was thinking of a spun bearing as well but wanted to see what others thought.

    Does anyone know what the effort is to replace the bears and if it is worth the expense or would to be better to go the rebuild route?

  6. JMoney02

    JMoney02 Epic Member 5+ Years 500 Posts

    Depends on your time, wallet and how much do you want to do. Since you have to take it out to do the bottom end, you may as well do the top end as well. So now you have gone this far and if you want it stock you then could go with the rebuild. If not you then do an exchange and warranty with rebuilder, will improve the purchase. If you rebuild it you can give yourself a warranty, you will need to redo if something is broke and you did it, but same goes for the warranty from a rebuilder, except they paid for the parts. You also can have them do it complete, a Company called American Engine Rebuilders is in business United States wide, google them and see if they are in your area and check out the cost...

  7. CLMonti

    CLMonti New Member

    Jeff -

    Thanks for the input - Greatly appreciated! I will check out American Engine, any thoughts on this company vs a Jasper?

  8. JMoney02

    JMoney02 Epic Member 5+ Years 500 Posts

    Chan, Nope, get estimate from both, ask about the warranty ifo and compare. Also see if they will give you any references to check their work. Good Luck and let us know what you outcome is......
    You Welcome, anytime...


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