2000 5.4 with knock at low RPM
Senior Member
Joined: Jan 2006
Posts: 2,835
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From: Vienna, Georgia
Originally Posted by Neal
HI!... Not really, you must deal with some real SLOW mechanics. Timing chains can be changed in like 4 hours.
I believe what you are hearing is the famous 5.4 piston slap. Because the 5.4 has such a long stroke the piston skirts are VERY short. When the engine is fired up cold it takes a bit till the piston actually heats up and expands slightly in the bore making it more stable. The cold start knock is just basically the pistong wobbling in the bore ever so slightly. Don't worry though I have never heard of a engine failure do to this. My 5.4 did this from day one and it had 200,000 KMS on it when I installed my new built 5.4. Bores were still in great shape and the pistons too.
I believe what you are hearing is the famous 5.4 piston slap. Because the 5.4 has such a long stroke the piston skirts are VERY short. When the engine is fired up cold it takes a bit till the piston actually heats up and expands slightly in the bore making it more stable. The cold start knock is just basically the pistong wobbling in the bore ever so slightly. Don't worry though I have never heard of a engine failure do to this. My 5.4 did this from day one and it had 200,000 KMS on it when I installed my new built 5.4. Bores were still in great shape and the pistons too.
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Member
Joined: Feb 2006
Posts: 14
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From: Colorado Springs CO
Thanks!
Thanks for the tips guys. It was a broken stud on the right rear manifold. Should be an easy fix. Good call Mitch! https://www.f150online.com/forums/im...ies/rocker.gif
