Does anyones 5.4 liter knock when you first start it? Mine does it and stops about a mile down the road? Why is this? What can I do?

 

What viscosity oil are you using? How many miles do you have?

 

Its probably just piston slap.

Search for "piston slap" and you'll get alot of info.

Its very common, and you shouldnt be too worried about it, at worst it is a little embarrasing.

Mine does it when it is cold enough.

 

Mine sounds terible in the morning, especialy when it's been sitting a couple days. Mine's been doing it since the truck was about six months old. Almost two years old and 40,000 miles now. Doesn't seem to hurt it a bit. It's piston slap like johngs said. I use 5-30 Mobile 1 and don't want to switch. I always sit and warm it up before I take off. Read up on it like was said and you'll feel better. If it was a major problem we'd be seeing alot more posts on it. Good luck, Carl

 

I see which oil making a big difference in worn rods and mains and especially in valve train components. And the piston below the rings does ride on a constantly wiped on/wiped off film of oil. But oil differences changing piston slap? Has anyone with piston slap tried different oils to see if some oils stop it?

 

Read this:

Everything you ever wanted to know about piston slap 4.6 & 5.4

That should about cover it......

Jamie D.

 

Some model years call for 5w20 motor oil. I had one in the shop yesterday with the same symptom(on cold start up). He was running 5w30. I switched him over.

 

Thanks alot guys!! I feel better knowing that its nothing major wrong with the motor.