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2.9 random knocking


johngalt14

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I realize the 2.9 is known for making noise, this however seems kinda severe. Makes some of the normal ticking, but after driving about 10 miles a much louder knocking becomes audible. Come back out of the store and take off, and it is back to normal. Kinda random, oil pressure shows good, any ideas?
 


adsm08

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Oil pressure gauge on the dash is an idiot light.

Try a real oil pressure test, but any real knock indicates internal engine issue.
 
truckerdawg

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Not a definitive answer. Just a possibility, not a probability. Pistons knock when the block heats up a lot(when it is running) and quiet down when cold or much cooler and can be attributed to broken piston skirts, broken rings, anything that would allow a piston to rock in the bore.
 

RonD

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After engine warms up pop the hood and listen if you can hear the knock at idle.

If so, pull one spark plug wire at a time, yes it will miss, then listen if knock is gone.

If you have a rod going out disabling spark in the effected cylinder will reduce the knock noise.
If this happens I would recommend you don't drive vehicle.
Right now you may just have a bad rod bearing but good crank and block, if rod breaks you could lose the crank and/or the block.
 
truckerdawg

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Oh yeah! Like RonD said. That baby can throw the piston clean through that block messing up a lot more. Built 302 kaboom! And I thought it was just a lifter ticking.
 

Hitchner2009

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Sounds like the usual rod knock from a 2.9 when she gets old and worn out. Mine is doing the same thing, i have a lifter tick thats HORRIBLE and when she warms up, she knocks. Thank god the 4.0L swap is right around the corner, counting down the days to March 7th!!! :headbang:
 
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