Slight Knocking sound at start up

[vince7870]

There's an oil additive called power punch. It keeps the oil up on top and prevents dry starts. Most new fords do the knock. My truck does it too. The punch stops it.

how much do you add?

 

[Stainless Works]

Also check for exhaust leak, especially if off-roaded, prob not the problem but worth it to look over. We have removed many oem exhaust components and a number of them show exhaust leaks from bouncing around and making contact with objects such as rocks, trees etc...

 

[Az Scooter]

It is the nature of synthetic oils. They stay thinned, so they bleed down quicker. I haven't noticed it in my truck, but no doubt, I will the next time I go out and start it.

 

[BIRDMAN]

Yup I get it occasionally too. Sounds like an old GM motor with a thrown rod for 2 seconds.

this is what i mean


1990 chevy 4x4 s10 4.3 throwing a rod - YouTube

 

[Delco.raptor]

Normal from the oil draining back after it sits.

 

[GotExhaust.com]

The 6.2's have hydraulic lifters. They are the link between the cam and valve. Until they fill with oil, there could be some movement or "lash" in the rocker arms which will cause a knocking or tapping at startup. Just a thought, not speaking from fact.

 

[rbarn]

Probably just some piston slap on cold start up. As soon the pistons warm up and seat into the liner and it goes away. Common on modern V8's.

 

[Bill_C]

I would agree with Got Exhaust. My soon to be gone 5.4 does the same thing in the morning. It sounds like lifter tap from the lifters bleeding down. This sound is nothing compared to starting up a 7.3 power stroke in the middle of winter with 20w50 oil in it. Mine used to sound like the engine was coming apart. Especially when it was below 0 and you turned the key and you could almost hear each individual cylinder start to fire. Talk about a racket.

 

[Mike P]

Mine is 3 weeks old, it does the same. I was worried but feel good now with this post

thanks all

 

[MTF]

Mine is 3 weeks old, it does the same. I was worried but feel good now with this post

thanks all

Your in the 6.2L section, you'll need to go to the 3.5L section.
But all modern engines with light oil grades will have a little tapping at startup.