Hi guys, I have a 1998 Expedition Eddie Bauer. It has the 5.4L engine. Also it has 80,000 miles.

About 4 months ago, a cold-start knock arrised. If I left the truck out-side all night then started it in the morning it would make a faint knock for about 15-20 seconds.

I then went ahead and switched the truck over to 5w-30 Full Synthetic motor oil and a motorcraft filter. This completely stopped the knocking (so I thought).

Four days ago I took the expy on a 650 mile trip to vegas. The truck ran great the whole way there, it didn't miss a beat.

THen when I arrived in Vegas, the problem arrised. When ever I waited about 5 hours then went to start the truck up, it would KNOCK very loudly for about 45-60 seconds. That worried me a little. I checked teh oil and it was full. It's been doing this now for the past week. If this persists I will sell the truck. Really I would like to keep it.

So if anyone here has any ideas to what causes this I would really appreciate it. By the way, the truck will burn 2 quarts of oil every 2500 miles. NO smoke shows up out of the exhaust though.

Thanks in advance for the help!!!

 

Come on guys....share some information!!!

 

Have you done a cold compression test? Had the oil analyzed for metal particles? Used a stethoscope or a piece of tubing to find where the knock is coming from? Looked at the spark plug on the cylinder doing the knocking? A valve might do this if the valve train is malfunctioning but I suspect you would get an engine code and check engine light. A collapsed oil ring might behave this way intially. In any case, avoid driving until you find the problem, to prevent any disaster.

 

Hey Bronco351,

You're looking in the wrong spot...instead of the Expedition / Navigator heading try the thread "5.4 Cold Engine Knock" under the heading: Engines 4.6, 5.4, & Modular... there's about 50 responses describing broken rear exhaust manifold bolts on the passenger side, defective timing chain tensioners and the classic "piston slap" due to modular design.

My 99' 5.4 has had the same condintion for the past few months. Synthetic helped until winter arrived. Clatter lasts for about 30-45 seconds at cold start. From what I've been reading sounds like it's the nature of the beast.

Good luck.

 

Thanks for the responses guys.... I'm going to do that compression test this weekend. I suspect it wont be too good due to all the burning oil.

One quick question, do these beasts have aluminum or cast iron cylinder heads???