My 99 knocks until it is warm, but I think it is piston slap.

 

Sounds like the common piston slap to me. The piston skirts were made shorter to save weight in these engine, but it lets the pistons move around just a little bit when cold. It won't hurt anything and goes away as the engine warms up and everything expands.

 

mattd I change the oil every 3,000 miles i use havoline 5w30 and i run 89 octane to cut down on the spark knocking which is different from this sound

 

I bet you guys are all wrong. If he is not using a motorcraft oil filter, then it will dryknock, its due to the lack of a proper anti drainback valve in the oil filter.

 

Doesn't sound like a dry filter start-up to me. It would do that as soon as you start it, not when accelerating. If it is detonation when cold, then a PCM reflash by the dealer should fix it. It could also be a small exhaust leak that seals as the manifold heats and expands.

 

Rather than complain about the noise just accept it and worry about things that deserve worry. My 98' 5.4 has 190,000 miles on it burns no oil, goes 5,000 miles between oil changes (10w40 castrol and motorcraft filter) and sometimes make the noise. Untill the noise doesn't go away after a few seconds I'm not going to let it worry me. It seems like a lot of motors were changed for not a lot of good reasons!!! Wonder why vehicles cost so much. HMMMMMMM! After my new heads are installed I expect to get the other 300,000 miles left in the lower end!

 

Has anyone had any experience in MA with the 5.4 being replaced? If so would you please share with me the dealership that was willing to do this and the ammount of persistance necessary? My Dad has a 2000 EXPY with a 5.4 and 70K. He complained at approximately 30K They gave him the BS TSB that it was normal. I think it sounds like my PSD myself! Just doesnt pull the same...lol.....Thank you.

P.S. Waranty coverage to 100,000 through Ford.

 

I have a '97 Expedition which started knocking cold at about 50K miles right after it ejected a third spark plug and the dealership replaced the head. The dealer told me it was piston slap but could not explain its sudden appearance. At about 100K miles, the knock started occurring any time the engine had no load -- i.e. at the moment between acceleration and deceleration. At 110K the engine froze. I had lost faith in the dealership, so I took it to a small "third world" shop that was willing to do an inspection of the lower end for a reasonable price. The number 4 connection rod bearing was completely shot -- worn nearly through and heavily scored, as if no oil. The other bearings showed NO measurable wear, perhaps due to use of synthetic oil throughout the life of the engine. From this experience, I urge you to get that engine replaced. Bottom end knocking is not normal, and I simply don't believe these engines suffer piston slap in the absence of serious damage to the pistons. If you have only 2.8K miles on your truck, Ford should provide a rental car free of charge.

 

See below.

 

I have a '97 Expedition which started knocking cold at about 50K miles right after it ejected a third spark plug and the dealership replaced the head. The dealer told me it was piston slap but could not explain its sudden appearance. At about 100K miles, the knock started occurring any time the engine had no load -- i.e. at the moment between acceleration and deceleration. At 110K the engine froze. I had lost faith in the dealership, so I took it to a small "third world" shop that was willing to do an inspection of the lower end for a reasonable price. The number 4 connecting rod bearing was completely shot -- worn nearly through and heavily scored, as if no oil. The other bearings showed NO measurable wear, perhaps due to use of synthetic oil throughout the life of the engine. Hence, my knocking was improper wear of one connecting rod bearing.

The noise it made was reminiscent of an old stuck hydraulic lifter -- i.e it occurred once every one or two revolutions of the crankshaft. If the knock is eight loose pistons slapping, I would expect to hear a rapid stacatto clatter, not a once-per-crank-revolution knock. If only one piston is "slapping" I would expect to find something wrong with that piston. With due respect to the many who believe they are hearing "piston slap" I don't understand why pistons with short skirts should be greatly more prone to "slaping" than long skirt pistions in the absence of serious, unusual wear. What evidence do we have that these noises many hear are the result of piston slap. Has anyone taken a "slapping" engine apart to measure the holes and the pistons? Why do some 4.6/5.4 engines make the noise, but most do not. It hard for me to believe that any noise on a cold start is normal. Mine never made any cold start noise before the dealer took it apart. From those of you who have concluded the noise is "piston slap," I would like to hear the reasons for this conclusion, and I would also like to hear some suggestions about alternative causes. I mean, are these noises once every revolution, or are they four or eight times every revolution? What IS the cause???

 

That sounds like a reasonable question Scot. The only reason I know about it is from a mechanic I know at the dealer. I understand what is said about the cause but you raise a good question. Mine does not sound like all the pistons, only a few. Wouldn't they all make the noise. The story I got from the dealer is that "that's what they sound like and we don't do anything about it".

 

I know. I got the same story from my dealer, and then I found out that the number four connecting rod bearing was dissolving. I got the Expy running by have the "third world" mechanic file the crankshaft smooth, mic it, and put in an appropriate oversized bearing in that position only. These mechanics who learn their trade in less affluent societies can do amazing things. The engine runs well with no morning knock, but since I did not find out what caused the bearing to fail in the first place, my next project will be to replace the engine.


It cost me $600 to have the oil pan dropped and the bearings checked. If I had caught the problem earlier, I might have been able to save the crankshaft from injury.

 

How come the noise is only there in the winter? If it was a mechanical failure in progress wouldn't it always make noise? It goes away as the weather gets warm, which would point to a piston clearance problem I think. Although I am no expert with the newer engines. Much of what I know is by hear say, not from doing it. My experience is with the older cars, 60s and 70s.

In any case I don't think ford is being honest about the problem, and we may never know what it is for sure. And we will always be ejecting plugs and hearing the "noise".

 

I would have to agree with your problem. I have a 97 F-150 and it does that too. Mine has done it pretty much since new and it doesn't seem to get ant worse. Must be a problem with that motor

 

I have it also, but only every once in a while, cold startup only, goes away in just alittle bit, I use Motorcraft oil filters and Mobil 1 synthetic, have 158 thous. on truck, I do this for a living and have for 31 years doing it, I believe in my case it is a lifter that has drained down its oil or a valve guide that has rooted out and is sliding the valve off the seat instead of a straight on seat fit. Either case, mine is in the head. If I remember correctly, I asked a high end engine rebuilder about this, that is what he also said, it is in the head. Broken Wire