philcomm

99 F150 w/ 5.4 with 97,000mi. At initial morning
start up, I get a loud knocking that goes away within
1 min. I can still hear a faint knocking later, but that
also seems to go away. I live in Mountains and it does
seem to be louder the colder it is.

Supercrewchick

Greetings. Let the techy guys have a moment to think and ponder. They should have some advice for you soon. You have come to the right place.

Buck

It sounds like its taking too long to get the oil pressure up. Maybe a bad oil pump. Im ASSUMING you have checked the oil to make sure it is at the proper level, as well as being changed at proper intervals.....

Also using the right oil for the temperature its being operated in. I know in some vehicles, lighter oils are recommended for colder climates.

philcomm

I always change oil at 3k + filter. Oil press indicator
shows normal at start--knocking continues for awhile.
sounds more on pass. side.

obusnizzle

the OEM pressure gauge is just an idiot gauge. You most likely have rod slap, the rod bearing(s) is shot.

kc5gxl

It could be several things. Worn oil pump, main bearings, lifters, rocker arms, etc. Is it a low, dull thud or knock? is it a high pitched tapping? A dull thud could be, and quite probably is, a worn main bearing. When oil pressure builds up and fills the void, the knock goes away. If it is a high pitch tapping, it is quite possibly a lifter that is losing it's prime on long period engine shut-down.

Just some ideas.

Good luck and keep us posted if and when you find out what the problem is.

Dan Harriman 84 F150 lwb
Orange, Texas

SuperDave

Welcome to the show!

philcomm

it's more like a high pitched tapping, sometimes quite loud, othertimes just barely heard. It's also louder on
the passengers side-as heard through the wheel well.
I would like to think it more likely to be a lifter, but I'm
an electrician not a auto mechanic. Thanks