What I'd consider to sound like lifter noise obviously isn't on this vehicle.

F150 5.4L has overhead, right? So, I've read that it's probably
piston slap - which sounds very bad to me - not being an engine
expert by any stretch of the imagination.

The sounds my pickup are making are only when it's cold, but have recently gotten worse. Seemingly this has gotten more pronounced since my dealership performed the 'engine flush' at 29,500 miles. Now, at 36,000 it is starting to worry me as the sound gets more pronounced - though it still goes away after the engine warms up a bit.

My question(s) are:

1. How bad IS pitson slap anyway? Is it something to worry about?

2. Regarding OIL. When I got the pickup in 2002, the dealer told
me it uses 5W20 synthetic. So, thats what I put in it. But I'm told
that 5W20 is only PARTLY synthetic. For the first year and a half
of owning this truck I was paying a BUNCH more for oil. Now,
about 6 months ago, I was told that 5W20 is only partly synthetic
and suddenly the price for the oil they put in my truck is much cheaper by about $15 per oil change. Can someone clear this issue
up for me?

Many Thanks!

Regards

-Craig

 

After doing some digging I found this excellent post on this subject.

https://www.f150online.com/forums/sh...&threadid=8747

Many thanks to the author!