4.6-V-8 (this is on a Mountaineer) (I believe its the same engine in the F150's??)


This morning, I go out as normal to start up the truck, the first 4 seconds or so after starting, it’s very smooth as normal, then to my surprise came a loud knocking noise that lasted about 5 seconds Max. What the heck could have caused this knocking to begin after it started up so smoothly? I turned it back off, waited 10 minutes to turn it back on to see if it would do it again, but it didn’t. Have any idea’s why it would knock so loud for just 5 seconds after running smooth the frist 4 or so seconds at start up?

I’m running Mobil 1 synthetic Oil with a bottle of the Locus Synthetic Oil.

 

You should look at other post on piston slap! I have the same problem at start up!



2000 F-150
4 x 4 Off- Road package
5.4 Triton
Line-x
Soon to have Magna Flow cat back

 

this was the very FIRST time I have ever heard this sound ever, and its weird that it did it just this one time, and I can't make it do it again?? It's weird, but it scared the hell out of me when I heard it this morning!

I don't care if it does it hear and there at start up as long as it's not going to do any damage to my engine??? I know if I were to take it to the dealers, I would not be able to have them hear it, so I guess if it gets any worse later on, then I'll take it in, but as long as it's not doing any damage then I'm okay with it for now....??

 

Unless it happens more regularly than that I would not worry.

 

You'll be fine, mine has been doing it for two years on so. I've had no problems, no leaks or loss of performance. I only really notice it when it's really cold!

 

I was going to post almost the same question, In the 3 years ive had my truck mine has done that start up knock 4 or 5 times. And every time it did it it was after a very short drive or a short start up then turn truck off.

For example you have company coming over and you have to move the truck 20 feet forward in the drive way and then turn it off.

Then you start it the next morning, not only does it do the knock thing but it also spits and sputters like hell and the whole truck vibrates? I have found that if I turn that truck off in cool weather before it does its idle kick down, I am screwed the next time I start it?

 

I've never had any sputtering or vibrations! It slaps unitl it warms up and goes away. Have you checked for trolls!

 

no, the knock will go away within 3 or 4 seconds, and the spit and sputter ends after I take control of the idle with my foot on the gas pedal. Kinda acts like a stuck choke. I also have no luck in cold weather starting When it gets zero or below I always have to help; the truck with my foot on the gas pedal.