Engine noise

[lasmacgod]

Reference the 2000 F250 in my signature:

I am not having good luck right now. The knocking from the rear axle I have posted in a separate post has now been placed on the back burner.

So, my engine has always made noise, I never paid much attention, figuring a high-mileage engine was entitled to make a little noise if it wanted to. However, I noticed yesterday that the engine is actually making a noise which sounds like a cross between a rod knock and valve train tapping. At idle, it is quiet. Revving the engine in Park, the noise sets in with a vengeance around 1800 rpm. It is not terribly loud, and the volume does not change with rpm. Above 2200 rpm, the noise is still there, but does not seem as intense.

To see if it disappeared under load, I held it in first gear and listened closely. The noise again kicked in at 1800 rpm. I held it in 2nd gear, same thing. In 3rd gear, I can't make it out over the road/wind noise. It is present whether the engine is hot or cold.

Crawled under with a stethoscope tonight, with the engine held at 1800 rpm, and the noise is definitely coming from the engine block on the driver side. In the stethoscope, it sounds like a harsh metallic tapping, very rapid. I checked the valve cover, timing chain cover, heads, oil pan, and bell housing. It was only heard on the driver side of the block when using the stethoscope.

Does this sound like wrist pin(s)?

 

[madibob]

Something to check, but I believe the V10 in that year had issues with blowing spark plugs out of the head when they become loose. This is a known problem. A friend had a '98 Ford pickup and blew 2 of them out on the V8. I think it was the 5.4L. They start to make some sort of ticking sound before they loosen and blow out of the head.

If you do find it's a loose plug with worn threads, there is a kit that can be purchased to insert a new plug. Otherwise the head would need to be replaced, depending on how worn it is.

Let us know what you find out.

 

[Hemi426]

196,000+ miles? What wt. oil are you running currently? Sounds like a wrist pin from what you say.

 

[willix]

A wrist pin will tear it up, blow major.

 

[Dualie]

Piston slap?

 

[Scienceman]

Sounds like the Ford has been a good truck!
Sorry about the problems it has now but you really can't complain!

 

[Schmoe]

It wouldn't be the infamous blowing spark plug. That particular noise sounds like a loose or broken exhaust manifold and it would have already blown by now. Strange it only happens at 1800 rpm, some sort of harmonic inbalance. Could it be timing chain slap? I think the V10 uses oil pressure to activate the timing chain tensioner. I would think piston slap would occur more at idle or across the rpm spectrum as opposed to a certain rpm. Other things like bearings and stuff wouldn't necessarily be at a certain rpm range either. Check out some of the F150 websites and see what you can find out. I'm pretty sure it's not that uncommon if it is a particular issue.

 

[lasmacgod]

Originally Posted By: Hemi426
196,000+ miles? What wt. oil are you running currently? Sounds like a wrist pin from what you say.


5W-30, just like it says in the manual.

Originally Posted By: Troy_Built
Sounds like the Ford has been a good truck!
Sorry about the problems it has now but you really can't complain!


It has been a good truck. Most parts were original on it until the past few months when everything started going downhill. You're right, I can't complain about the truck, but I can complain about having to break the news to the wife. She is not so understanding or sympathetic toward vehicles, thinks they should last forever, and is angry when they don't.

Originally Posted By: Schmoe
Could it be timing chain slap?


I don't think so, I ran the stethoscope around the timing covers with no results.



I had a suggestion from a friend to check crankshaft end play. Not real sure how that would be causing the noise though. I think that if it was the end play, I would hear the noise on both sides of the block, not just on one.

 

[mechtech2]

Timing chain stuff?
How about an oddball flexplate that is cracked or loose?

 

[CBR.worm]

Any accessories bolted to that side of the block? Exhaust heat shields or motor mount on that side?

Is it louder cold or hot?

Carbon buildup causing slight piston to head contact - i have seen engines run like this for a long time if they hit square, if not, the skirts tend to collapse.

 

[lasmacgod]

Originally Posted By: CBR.worm
Any accessories bolted to that side of the block? Exhaust heat shields or motor mount on that side?

Is it louder cold or hot?

Carbon buildup causing slight piston to head contact - i have seen engines run like this for a long time if they hit square, if not, the skirts tend to collapse.


There are accessories, but I hit all accessories with the stethoscope with no abnormal noises from any of them. Temperature of the engine does not seem to make any difference. That being said, when it is cold, it does have piston slap. Again, no abnormal noises when checking out the heads with the stethoscope. The exhaust shields were already removed by the previous owner, and motor mounts are still good.




I just went outside and started disconnected one COP at a time. When I disconnected cylinder #8, the noise I have been dealing with got quite a bit worse. Still in the same RPM range, but much more acute, more harsh, if that makes any sense.

This test did bring about a new observation. When any one of the COP's was disconnected, the engine knocked pretty bad at an idle. This knocking was a low pitch, similar to your typical rod knock. This may be something I duplicate again tomorrow after a good night's rest, and trace with the stethoscope. The engine ran smooth otherwise.

 

[Dualie]

Pull a UOA and see if any crazy wear metals come up.

 

[CBR.worm]

I have heard engines (Nissans) knock when missing due to a disconnected coil or fuel injector, I am not sure why - maybe general imbalance? They sound like they are going to come apart.

Interesting that unhooking #8 made the noise worse.

 

[mechtech2]

Can you disconnect the injector connectors while running?
Note that this and yanking the coils can throw a code which needs to be erased.

 

[lasmacgod]

Thanks for all the help everyone.

The wife apparently became jealous because I was spending all my time working on my truck instead of with her, because she told me it had to go. I would have loved to know what it was, but truth be told it's a relief not having to worry about it any longer.