Knocking noise???
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Senior User
Joined: Oct 2001
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From: Millersville USA
Knocking noise???
Looking for some suggestions my friends...My brother has a 1986 F150 with an EFI 302....he started having a knocking noise in his engine....we are unsure of what could be causing it...here's what we did so far...we changed plugs, wires, cap, and rotor...we also checked compression on each of the cylinders, and all were good...we cleaned the injectors, and throttle body...but still have the knocking noise...it's not real loud, and it doesn't affect the performance of the engine...any ideas what it might be??
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Joined: Nov 2003
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exhaust leak? could also be worn bearings. can you give us a little more info to work with, like where does it sound like it is comming from? We are all happy to help, but at least I need more info to make a educated guess.
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Senior User
Joined: Oct 2001
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From: Millersville USA
It's a real low sounding knock, and it sounds as if it's coming from deep within the engine....the manifolds are good and tight, almost sounds as if someone is using a rubber mallot and hitting the inside of the engine block, down deep inside it. He went to a dealership to pick uyp his wifes car, and it was fine, when he came back out, and started it up, it was knocking really loud...once we gave it a tune up, it still knocked, but not really loud....but you could still hear it. Thanks for the reply!!
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Joined: Apr 2003
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sounds like the rear main bearing , they make a deep single knock while rods make a higher double knock and don't run long. Piston slap is a sharper sound which goes away or is lessened as the motor gets warm, wrist pin knock is higher pitched. Is this noise louder or existent only at start up or all the time?
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From: Still under the hood in O
Get a broom stick and press it to the pan. If you hear it clearly there then a teardown is needed.
Also read this if coming from pan.....
http://www.autosite.com/garage/encyclop/ency01l.asp
If it isn't clear at the pan, move to the top of the motor (valve covers/exhaust man. etc) until you find it.
Also read this if coming from pan.....
http://www.autosite.com/garage/encyclop/ency01l.asp
If it isn't clear at the pan, move to the top of the motor (valve covers/exhaust man. etc) until you find it.
Last edited by 90f150moneypit; Mar 3, 2004 at 03:43 PM.
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