Piston Slap?

[fryguy]

Just wanted to get some opinions on the 1st gen 5.4.. I hear some people say it's a great engine yet occasionally hear people say it's junk.

On mine, I have a really bad knock for about the first minute or two in the mornings, once it warms up it's supper quiet. I've been leaning more towards piston slap going off my own experience.

Anyone know if this is something that I should address down the road? I'm pondering on taking this truck to Colorado this summer, other than the cold knock I think this is solid mechanically.


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[1955moose]

You want to get an oil pressure reading. Especially when cold. You'll need to hook up an oil pressure guage in place of oil pressure switch. You might have a partially blocked oil pickup. What weight oil are you using? These motors don't like too thick an oil, especially in colder climates. Recommended is 5w30. That's what I run in my 2000 5.4. How many miles on your motor?


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[fryguy]

Seems like the noise is coming out the the passenger side of the engine. I've been using 5W30 semi-synthetic oil for high mileage engines.

279,000 miles, so not surprised it's a little loud. But always a bit baffled because after it runs for a couple minutes it quiet, no knocks, ticks, nothing.


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[fryguy]

Did I mention it's LOUD, sounds like piston slap, but not 100% sure. Initially I thought it was a bad phaser, but they get louder as the engine warms up?


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[1955moose]

Well you got a few choices. 1 deal with it, 2 pull your pan, clean oil pickup and replace oil pump, 3 switch to total synthetic. I run Mobil 1, 5w30. It's slicker than semi synthetics, might help. Napa has had them on sale recently. Your eventually going to have to make a desicision about your SUV. It's high mileage.


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[fryguy]

So this is kind of a project vehicle for me. "Winter Beater" - hoping to get 350,000 miles on it, then I will be selling it or scrap it. I generally put on 35,000 to 38,000 miles in a year.

How difficult is it to change the oil pump? The oil pressure gauge reads good. Is it not an accurate reflection of the oil pressure?

I'll try out the full synthetic oil, I was leaning in that direction already for the next change. Planning on using Valvoline MaxLife Synthetic Motor Oil 5W30.


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[Flexpedition]

Without hearing it, it sounds more to me like a (fairly common) leaky exhaust manifold. They can slightly warp, sometimes taking a stud out with them. You can sometimes get lucky and tighten all the studs & nuts back snug and the noise goes away. If the studs are rusted you increase the risk of snapping them. Once the manifold starts to warm the noise goes away.

Can be difficult to view from above, easier to jack up front passenger side. With wheel removed, pull fender liner away to expose the manifold. If you can see soot on/around the manifold or on the block itself & smell gas fumes, then thats your problem. Count all the studs.

I personally wouldn't start using Synthetic on a 279K motor, especially on a project truck described as winter beater that'll likely be scrapped/sold in a year or two anyway.

Listen & compare to this random youtube:
https://www.youtube.com/watch?v=ZyPDZ8QHSBU

 

[docraymund]

Most probably it is piston slap. Confirmed if you hear a hollow bell like sound which disappears on acceleration. Unplug fuel injectors one by one. If noise disappears then that is the worn cylinder. If it occurs when the engine is cold, then its not that serious.

 

[fryguy]

Position Slap?

It's kind of like a hallow thud sound. Some mornings worse than others. My brother had a Chevy Malibu that made an identical noise, his was to the point of doing it all the time and was piston slap, common on GM's 3.1L V6.

When I had new spark plugs installed I asked the shop to check it out for an exhaust manifold leak, they confirmed that all was good, no leaks.

But could not advise on the piston slap as it was warmed up.

I'll try to get video of it one of these days. I'll post it here.



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[1955moose]

Exaust leaks have more of a ticking, rather than slapping sound. You can use a piece of hose up to your ear, run hose near all possible leak spots. A loose piston will slow or stop the slap as the pistons expand in their bores. As you said in your thread gm vehicles are famous for this, and usually run the full life of their engines. Pulling the pan isn't easy on this model, and you said you have good oil pressure when cold, so it would be a gamble at best. If your going to scrap it at 350k anyway, just ride it out. Worse case senario, you get rid of it early. Just keep your oil level up, and drive it. Our taxi cab fleet 4.6 motors would routinely go to 350k, on original motor.


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[DUNE RCR]

Just a little tid bit of info quick. Ford put out a tsb back in 2002 for the oil viscosity in a majority of the ford lineup to swap to 5w20 instead of the originally recommended 5w30.

Tsb article no. 02-1-9a if you want to look it up.

This applies to our 97-02 4.6 and 5.4 expeditions and f150s.
I will say that my 2000 f150 with 5.4 seemed to run smoother as well when I switched oil grades.
The tsb has a huge list of vehicles this applies to if you want to look it up.
Just a little food for thought.

 

[1955moose]

I've only got 80k on my 2000. I live in the Bay Area where it never gets below 35 degrees. You guys in the cold climates, it might be worth trying the thinner oil. These are tight clearance motors. With 5.0 liter Fords and all the various nissans I've owned, not to mention motorcycles. Had never had the issues that these 4.6/5.4 liter motors have. I used to run 20/50 oil year round in my vehicles. Then again we don't drop below 37 degrees here in San Francisco. I always love when a manufacturer sends a tsb to their dealers saying it's normal for a vehicle to exibit a certain problem, rather than fix it. Remember with big company's it's easier to make you go away than pay to fix the problem.


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[toms89]

No cam phasers on 2v motors so you can rule that out. A timing chain tensioner maybe? Hydraulic lash adjuster is another possibility I would consider. May bleed down while sitting and not fully pump up till warm.

 

[fryguy]

Position Slap?

A couple weeks ago I checked out the throttle cable, it was really stretched out. Only opening the throttle about 35 - 40% (I fixed it). Since then I have opened it up a few times. The noise I was hearing seems to be gone now.

Is it possible that I just had carbon built up that bad? Also ran Seafoam through it as well.


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[AbbadonTD]

You could have knocked something "worse or better" when you cleaned your throttle. my old 5.0 f150 would throw bolts when I cleaned out the throttle. I assume its the "engine shake" and that the cleaner throttle makes it bounce just a little "fiercer."

Maybe I am just cheap when it comes to motor mounts.

If you are going to come to Colorado for more than a few days, you may consider tuning your engine for our lovely elevation.

 

[1955moose]

Were sending some of our fog over to Colorado from San Fran, your air will be nice and dense soon!


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[1955moose]

Boy I thought I was the only one that had weird things happen to them working on vehicles! A loose throttle cable causing a cold start engine knock is one for the books!


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[fryguy]

Wasn't loose, it was just stretched out. Only opening the throttle 35 - 40%. Was like a day & night difference in power.


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[1955moose]

That was causing your cold start knock?


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[fryguy]

No, read the past post's...


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