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emorse
Novice
Nov 28, 2012, 8:58 AM
Post #1 of 12
(1893 views)
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hello i have a 97 ford expedition that has a nock at about 2000 rpms the motor a 4.6L with W code. I have about 161k on it and i maintain it very well but the motor just started nocking i did an oil change about 100 miles ago. any ideas
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 28, 2012, 9:32 AM
Post #2 of 12
(1869 views)
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? Just an oil change and now noise? Check oil level of course and that pressure is up to par. May or may not be internal engine but maybe a belt driven item.
A real engine knock from worn or bent engine bearings or a rod - something could be real trouble. May need to have a pro listen to it in person to get a best guess of the knock,
T
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emorse
Novice
Nov 28, 2012, 12:09 PM
Post #3 of 12
(1837 views)
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just an oil and filter change. i was thinking maybe some crap in the lifters but it sounds like the nock is in the bottom half. i was going to try a scope and listen to it too
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 28, 2012, 12:30 PM
Post #4 of 12
(1833 views)
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There's a whole list to check what we are calling "knock'' engine noises. Lifters and valve items are more apt to make ticking noises than a real knock.
You might find if it's one cylinder only by cancelling one cylinder at a time. Noise should change or go away. Note things like one dull knock or a double knock and if rhythmic with engine speed.
Does it do it all the time or just warmed up or cold type observations. This engine has quite a timing chain set up that to me has not been known for knocks.
My guesses include totally wrong oil viscosity a maybe or check that oil for being too full and smell of fuel - wouldn't be good news,
T
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 28, 2012, 12:32 PM
Post #5 of 12
(1828 views)
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Sorry - one more as a test. Take the belt off and start it to see just for a few seconds if noise goes away,
T
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 28, 2012, 12:32 PM
Post #6 of 12
(1825 views)
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I usually find that when engine noises occur suddenly after getting an oil change, it's usually because some fool forgot to put the oil in and started the engine and then tried to pretend nothing happened.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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emorse
Novice
Nov 28, 2012, 12:52 PM
Post #7 of 12
(1821 views)
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well i will try the belt idea and see if it goes away there. as far as not putting oil in and starting it i do all my own work i did the oil change myself so i know thats not the deal i even sub a quart of lucas oil for regular oil to extend life of the motor a little. as far as the noise its both warm and cold engine.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 28, 2012, 1:01 PM
Post #8 of 12
(1816 views)
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What is the exact Lucas product? I want to look up what it is. How long have you used that too? Not a fan of things like that. If you plain use quality oil and changed on time should be enough. I do approve of synthetic oils but not additives for much of anything. For oils generally either thickens viscosity or super detergent and if it needed either a problem already existed and would just be a patch at best,
T
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emorse
Novice
Nov 28, 2012, 1:35 PM
Post #9 of 12
(1808 views)
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its the lucas oil treatment its designed to help fill in scratches and pits in the cylinder walls ive used it on this particular truck sence it hit about 130k i also use napa gold filters with max life(red bottle high milage) oil from valvoline. im not a big fan of additives but this is one as a diesel mechanic i would use and tell others to use just for added security. never had an issuse.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Nov 28, 2012, 2:14 PM
Post #10 of 12
(1800 views)
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Probably not the issue but just the claim "fills scratches and pits" is a NEON light warning that it's crap! High mileage oil I can't say if it's any different. Oils are rated to have the properties as required by manufacturer with whatever additive already if called for so adding more of something worries me.
Diesel requirements are listed for those engines. Synthetics may or may not be the world but clearly tolerate heat better. All need changing regularly.
Back to the noise. You can rule out some. Again, double knocks, single knocks, knocks that only show under load or just free like a raised idle. When just one cylinder and cancelled from firing one at a time the noise should change and be tell-tale of what is likely. Each has a character for some common ones......
* Rod knock
* wrist pin knock
* main bearing knock + or cam bearing knock
* Dull deep sounds or lighter sounds
Some can fool you and not be the actual engine at all - perhaps a lose or cracked accessory bracket, pulley, belt itself, exhaust something??
T
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Discretesignals
Ultimate Carjunky
/ Moderator
Nov 28, 2012, 5:42 PM
Post #11 of 12
(1784 views)
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If you made a video and uploaded it to a hosting site and then pasted the link in here, maybe it would be easier for us to narrow down some possibilities.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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emorse
Novice
Dec 17, 2012, 7:46 PM
Post #12 of 12
(1709 views)
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well after a little digging i found that the number 8 conecting rod cap had spun. put a new crank and all new bearings in it and away it went running strong.
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