Knocking noise when starting?

Tiny
HOSSY2010
  • MEMBER
  • 1997 FORD F-150
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
When I start my truck when it is cold there is a knocking noise until it is warmed up can you tell me what it could be?
Sunday, February 8th, 2009 AT 10:05 AM

1 Reply

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,885 POSTS
Hi,

If you are hearing a knocking noise when it's cold, there's a chance it is related to an engine bearing internally. If there is excessive play or clearance in a bearing, you will hear it when cold. As the engine warms, the metal in it expands. The expansion often times will take up the excessive play and the noise will be less noticeable.

Here is a link that you may find helpful. It describes common engine noises and how they are fixed.

https://www.2carpros.com/articles/engine-noises

Always make sure the engine oil is clean, full, and has the correct oil viscosity.

If you look at the two attached pics below, I included the capacity and viscosity required for both the 4.6L V8 and the 5.4L V8.

I hope this helps. Let me know if you have other questions.

Take care,

Joe

See pics below.
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Sunday, August 1st, 2021 AT 8:44 PM

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