Loud knocking on cold start.
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Tuned
Joined: Jan 2010
Posts: 470
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From: San Diego, CA
Loud knocking on cold start.
Every time I go and start my 2001 F150 4x4 5.4L, when its cold the right bank knocks for awhile until its warm. What is this? Has anybody else had the problem? I don't think its a cam phaser because I have heard those and this is a more pronounced or solid knock. Phasers are more of a ticking sound. Lemme know what you guys think. Thank you.
Postmaster
Joined: Nov 2006
Posts: 4,517
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From: SE Wyoming
Does it do it when it is say 90* out? Sounds like piston slap mine goes away when the engine reaches about 140*. Middle of the summer I either can't hear it or the whole block is just warm enough it doesn't do it.
Posting Guru
Joined: Feb 2007
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Not sure. Still tend to associate "Phasers" w/'Star Trek'.
When hydraulic valve lash adjusters get old & cranky from accumulating wear & crud, they can 'collapse' & become slow to 'pump up' again.
Exhaust manifold leaks I've heard seemed to be "loud" hot or cold.
Have seen some comments about "piston slap" that might be found using Search. Must have it backwards though? Thought "piston slap" reared its head by 'rattling' at cruising speed, or appeared when you got off interstate, at 1st red light & new sound, more than "ticking" made you worry about motor? Missed it being cold start/cold weather related. Did get the impression "piston slap" wasn't usually a dire emergency?
Any "Loud knocking...solid knock" would sound very serious to me. Got the impression "piston slap" can be kind of a marginal symptom & judgment call. What mechanic might consider normal motor sounds, a worried owner might think of reason enough for a warranty motor.
Have heard complaints of fuel injectors being "loud".
Using FORD specified oil?
Exhaust manifold leaks I've heard seemed to be "loud" hot or cold.
Have seen some comments about "piston slap" that might be found using Search. Must have it backwards though? Thought "piston slap" reared its head by 'rattling' at cruising speed, or appeared when you got off interstate, at 1st red light & new sound, more than "ticking" made you worry about motor? Missed it being cold start/cold weather related. Did get the impression "piston slap" wasn't usually a dire emergency?
Any "Loud knocking...solid knock" would sound very serious to me. Got the impression "piston slap" can be kind of a marginal symptom & judgment call. What mechanic might consider normal motor sounds, a worried owner might think of reason enough for a warranty motor.
Have heard complaints of fuel injectors being "loud".
Using FORD specified oil?
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