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Thread: Engine Knocking...what does that mean?

  1. #1
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    Default Engine Knocking...what does that mean?

    Pretty sure I hear a repetative knocking sound coming from the engine at about 1/4 sec. intervals. When I hear the sound the first thing that comes to mind is it is an engine knock. What does it mean when your engine knocks? What fixes? 5.2l

  2. #2
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    Tell us some more info. Does the knocking get faster as rpms rise? Whats your oil pressure? Is it coming from towards the oil pan or more from bottom of the engine instead of from the top? Also how many miles are on it?

    Jason
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  3. #3
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    It has 115k on it but it usually runs very well, not at all like you would expect an engine with that many miles to perform. It just started a couple days ago. My Oil Pressure sits at just about 45-50 and is pretty constant. If I had to categorize the knock as a slow, medium, or fast paced knock, I would say its a fast knock. As far as increasing with rpms I would say it does. I dont know if yall have seen The Hunt for Red October but it sounds just like the sound "jonesy" (the sonar guy) plays to the captain at " ten times speed". The catapillar drive. Anyway, I think the vehicle is in need of a tune up (wires, plugs, etc) and I was wondering if that might cure it. What are the "usual suspects" when hearing knocking? Is there a "test" I can perform to affirm or eliminate things? Thanks.

  4. #4
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    Knock-type noise posabilities:

    1)lifter tap: Usually increases in speed wiht RPM's, worse at startup. Not really a big deal, but can be indicative of other problems.

    2) Spark knock: Caused by overly lean A/F ratio. Usually only occurs whn you get on it hard under load. Can be remidied by 1) retarding timing 2) using colder plugs 3) determining cause of lean mixture. 4)finding/fixing vacume leaks. If you think this is tha case, pull a pluc and read it. white=lean, black=rich, golden-brown=right

    3) wrist pin knock: Clearance/oiling problem in th piston wrist pin bearing. Your motor will live, just get used to it.

    4) Rod knock: Its all over, she ain't got much more left. if you wind it out, it will come apart (especially SBC's) Most likely, this isn't what is going on.

    5) Timing chain slap. TIme for a timing chain. I have only seen/heard this once, in a Chev 305. most likely, this isn't it.
    "Built, not bought"
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  5. #5
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    Could be the O2 sensor. try changing it. Use only a mopar one or get the one kolak@aol.com sells. For some reason the 5.2 does not like any other O2 sensors and non-mopar PVC valves. You may want to get a can of Mopar CCC or Sea Foam to clean the cumbution chambers--Or use High octain gas and see if that helps.
    2003 GC, upcountry, select trac, 4.7.

  6. #6
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    You can go to your local parts store and get an isolator, it looks like a stethoosope with a metal rod on the end. You just touch it to where you think the knock is coming from. That ought to help isolate it...

    Greg
    99 WJ, 4.7L, Clayton's LA, BFG Mud Terrains 315/75/R16, K&N FIPK, rear Addco, Kevin's Sliderz, Surco Safari rack, VIAIR 450 OBA, Kolak exhaust, ARB bumper, Warn HS9500, Xenon's w/harness... more to follow

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