Need help diagnosing these noises

Today I was towing a trailer to pick up some metal. I thought I heard a weird tick that seemed to be in time with engine RPMs, but I wasn't sure. About 2 miles from home, the truck started making a terrible racket, like I was dragging a barbed wire fence or something. I didn't really want to deal with abandoning the trailer and metal (stuff's expensive these days) and getting it towed, so I risked it and drove it the rest of the way home.

To me the clatter sounded kind of sheet-metal-y, so I assumed a rocker had maybe given up, or a broken spring or something. So I pulled the valve covers, everything is fine there. Pulled all the spark plugs, they all looked good. Ran a compression test on all cylinders, all around 150psi. The engine never seemed to struggle and the truck drove normally, just a bunch of noise. After I put the top of the engine back together, I thought it might be a flexplate nut had backed off. Pulled the inspection cover and all looked normal in there.

I started the truck and tried to get a couple of videos of the truck making the noise. The noise seems to be coming from the oil pan or transmission bellhousing area. It seems a bit louder to me by the bellhousing. The torque converter is the original 1995 stock unit, which I'm told were prone to ballooning, but I have no clue what that would sound like, and I thought those problems manifested themselves at high rpms. These videos were taken at idle. Any good guesses, anyone?

https://www.youtube.com/shorts/AIzeQyBEmfE

https://www.youtube.com/shorts/BlWobcYScx8

In the videos it sounds strongly like a rod knock, but in real life it is different than that. If you listen carefully, there is a kind of screechy component to it, not just a knock. Oil pressure is good and never dropped.

One more thing that might be a clue is that the previous 2 drives to this one, the transmission took its time dropping into gear. I had written this off as it getting cold, reducing the fluid volume, and I needed to add a bit. That may still be what it is, or it might have something to do with what's going on now, I don't know.

Wow!

First thing I thought of was something on the flex plate was bad, but you checked that.

If the tranny was acting up I would be suspicious. I've never heard a tranny make a noise like that, but it is an E4OD and some have had problems.

I associate E4OD problems with torque, I had a 94 F250 with a 460, with one and it was problematic. I have one in the Bronco and it's great.

I also might think water pump but the noise seems too far back.

I'm not helping, but boy, that sounds terrible!

The audio is really difficult for me to interpret.

If you think it might be coming from the transmission I think the old pry bar handle to the ear 'stethoscope' would pinpoint that as the cause.
Also, id think a transmission noise is going to change with gear or road speed.

If it strictly follows engine speed and gets louder under load i'd suggest you have an exhaust leak.
This also might explain your whistling component.
A few feet of vinyl tube (3/8"? ID) will let you listen close along the flanges and pinpoint a source.
I know that periodically the inside bottom of #8 on my truck will get to leaking, and sound like a bad valve tick.

Good luck Pete. I hope you find it soon.  

Good thoughts. Water pump is new-ish, about 2 yo. I replaced it when I built the engine. One of the tests I need to perform is to take off the accessory belt and see if it still clatters. I really don't think that test will prove anything, but I don't want to tear the engine out only to find it was not in the engine itself, so gotta do the due diligence.

This particular E4OD is not highly stressed, torque wise. I am pretty gentle on the throttle, MPG is already in the 10 range so I don't need to make that worse. It was pulling a 2k lb trailer when it happened though, so anything's possible.

I still haven't ruled out a problem with the flexplate. I can only see a little bit of it at a time through the inspection cover. I do wonder if one of the 6 bolts in the crank could have backed out. Guess I would not be able to see that unless I separated the engine and trans. They were loctited and torqued properly, so I don't think that's it, but like I said, anything is possible.

Thanks for the response!

I did do the hose trick, but the noise is so loud under there it's difficult to isolate. It did seem louder in the bellhousing than in the pan, but it's hard to say since the bellhousing was open and the pan was closed, so the sound just might be louder because it's got a place to come out.

I'm relatively sure it's not an exhaust leak but I will double check that. Too much clanking going on.

My BIL suggested that the dipstick might have fallen down into the crank, which was a brilliant thought, but that was not it.

I'm stumped by "inside bottom of #8 gets to leaking". #8 is cylinder/piston 8? What and how does it leak?

I think my next move is going to be to see if my snake camera fits in the oil drainplug hole. I have to wonder if some kind of baffle in the oil pan has come adrift. Or maybe I can spot a rod cap coming off or something.

Question: to drop the pan, is that an engine-out proposition? Looks to me like there's only about an inch of clearance between the bottom of the pan and the crossmember. Is it possible to pull the engine up enough to snake the pan out of there, or am I dreaming?

Thanks for the response.

I'd think you would see some metallic flakes or a really shiny bolt head if a flex plate bolt had backed out (and become a crude fly cutter)?

You can poke the hose around from the top where you're not surrounded by noises.
The metal lamination of an exhaust gasket can screech like a blade of grass between your thumbs when you blow through it.

My initial probing had me thinking my tick or clatter might be coming from the LH headpipe to manifold junction, but working with a cold engine so I didn't burn my hand it became very clear that it was the bottom of the #8 exhaust port nearer the side facing #7.

Don't discount the old screwdriver to the ear trick or even an actual mechanics stethoscope with a solid wand.
These are cheap enough at places like harbor freight.
If the noise is coming from inside a case or block you will know right away.

Pete Whitstone wrote

Question: to drop the pan, is that an engine-out proposition? Looks to me like there's only about an inch of clearance between the bottom of the pan and the crossmember. Is it possible to pull the engine up enough to snake the pan out of there, or am I dreaming?

Gary said it was possible to get Brandon's 4x4 351 pan out with the engine in place but that it took the lift, a transmission jack and both of them all day to swap his oil pump.  
Also that he would never again waste his time as it's easier and quicker to pull the engine (in the Garagemahal)

I can't really speak about doing it with a Windsor.
With a 4x4 460 or 420 IDI definitely not happening.

Amen, Brother!!!

it is really difficult to hear well enough to diagnose but it does seem to be torque converter centered. I wonder about a failure in that. not that I think it's a common thing. just that it does not seem to be as repetitive as a rod bearing or a cracked flex plate flexing. more like rotationally random. in fact, it does sound like a broken exhaust hanger in a way.

on a second note. pull the engine to gain access to the pan. ironically this was just tried today. now the engine is getting pulled in the morning. I tried to say this, but I guess the guys needed to see for themselves. sad thing is that we were firing a fresh rebuild and after 15 min running to set the cam a rocker started tapping and oil pressure went away. so tomorrow to forensics begin.

It sounds like a broken flex plate to me. You can't see the damage until the trans is out of the way - they break just outside if the bolt circle.

Pulled the engine but haven't found anything yet. Flexplate is fine and no bolts have backed off. Nothing in the oil pan, all main cap and rod cap bolts are tight. Oil is clean with no metal shavings in it.

Next step is to take the intake manifold off and make sure everything is ok with the cam/lifters. That seems kind of doubtful, as all cylinders tested at about 150 psi on the compression test before the engine was pulled. The only thing I can think of there is that an exhaust valve has a problem, my theory being that if an intake valve was not opening I would not get compression but a hung closed exhaust valve would still give a compression reading.

I have a (possibly stupid) plan to see if the noise is in the TC/trans... I am going to bolt the flexplate to the TC, bolt the starter back on, and bolt something to the bellhousing that provides a stop to prevent the TC/flexplate from coming out. Then spin it with the starter. I figure with no engine compression to contend with, it could spin the trans at speeds that might be close to engine idle, which should produce the noise if it's coming from there. Any thoughts on this?

I thought you had the valve covers off and barred the engine over?
Surely you would have found a tight valve or bent pushrod?

Do you have a PMGR starter?
I'm not too familiar with exactly where the crank flange of a Windsor sits in relation to the plane of the bellhousing..

ArdWrknTrk wrote

I thought you had the valve covers off and barred the engine over?
Surely you would have found a tight valve or bent pushrod?

Do you have a PMGR starter?
I'm not too familiar with exactly where the crank flange of a Windsor sits in relation to the plane of the bellhousing..

I had the valve covers off for a visual inspection and did not find any rockers off the pushrods, or any loose lockers, or anything out of the ordinary. I did bar the engine over and observe everything and didn't see anything out of the ordinary, but that doesn't necessarily mean that something didn't move when it should have and I didn't notice. It's a very long shot, I realize. But I have to cover everything.

I don't remember exactly what kind of starter is on there, but I'm pretty sure it's not a gear reduction starter. I need to take a close look at the starter, probably should have done that before I yanked the engine. The flexplate ring gear does not look chewed on as far as I can tell, so I don't think the problem is there, but I have to cover everything.

I plan to build a test stand that I can put the engine on, then rig up something with the bellhousing bolts so I can put the starter on it. Then I can try to start the engine on a test stand to see if the noise is coming from the engine. I'd be really hesitant to put it back in without doing this. But since the engine's fuel and spark are controlled by the ProFlo system, I'll have to throw a conventional dizzy and a carb on it.

I went back and listened again to the two videos, and it seems very flex plate oriented .it passed inspection so the next likely cause from the sound seems to be a failed torque converter. if you can collect a bit of trans fluid in a glass jar, preferably from the outgoing fluid line, you should be able to test for steel filings.

I will try to cleanly collect some fluid and see if it has steel in it.

I did try the "bolt the starter on and spin the TC" test. It was inconclusive, no noise was made like the noise in the videos, but the starter could only spin it about as fast as it does when starting the engine, I thought it would spin a lot faster without the drag of the engine on it.

So I continued with engine teardown. Took off the intake manifold and took out all the rockers, pushrods and lifters. Did not find anything unusual. But while I was doing that, I noticed a little clump of blue painters tape that I had shoved in a hole at the back of the block to paint it. Here is the hole, on the passenger side (block is upside down, oil pan facing up, in this picture).



It was open but for the tape that was shoved in there. I squirted some brake cleaner in there and it seemed to drip out of the crankshaft, only a few drops, but it made me think that passage might be open to an oil gallery. So I pulled the nearest main cap and rod cap to see what those looked like. Here they are:





Now, there has always been a small oil leak somewhere, I thought it was rear main seal. And then after pulling the engine and finding oil higher up, thought it might be a poorly sealed rear china wall. But now I'm wondering if this thing had oil coming out of it.

If it did, it had to be minimal. It has always had good oil pressure on the gauge (30-60 depending on cold/hot/rpm) The truck could drive thousands of miles and not go a quart down. And it could not have been coming out of there under any pressure at all, or it would have blown the tape wad out long ago.

So I don't know if this is anything or not. I pulled the rest of the main bearing caps and looked at the lower bearing shell, they all looked similar to the one in the picture. I have not pulled all the rod caps but I did verify there is no real clearance gap on any of them (like you would expect a rod knock to produce).

So what is that port? And what are the thoughts on those bearings? The truck has maybe 8-10k miles since rebuild. Do those bearings look consistent with that amount of miles?

Thanks!

Knock sensor

Edit to add, link to FTE:  https://www.ford-trucks.com/forums/1565706-351w-block-question.html

Bearings look normal. 🙄
How do they feel if you run your fingernail across them?  It's hard to tell things on my phone.

the hole is a mounting point. a knock sensor fits there on some car models I believe. 5.0 truck blocks have a second port just like it on the top of the block also. not a cause of an oil leak. if you look immediately behind it, you can see that it backs up to the open area into the bell housing area and there are no cross drilled oil galleries in that area. as far as the bearings go. they don't look bad but also don't look perfect. there is a good long contact pattern, but I see some signs of dry start and or trash. Certainly not to worry about but keep it oiled. it's funny how many engines I have pulled down which made no noises at all and had an amazing amount of tolerance with bearings well into base layers. one was only getting a rear main seal because it kept leaking so I did a wiggle test and showed the trucks owner his crankshaft moving around in the seal. the new seal helped for a little while and he kept driving it for another couple years without any noises until he got another and swapped it out.

ArdWrknTrk wrote

Knock sensor

Edit to add, link to FTE:  https://www.ford-trucks.com/forums/1565706-351w-block-question.html

Bearings look normal. 🙄
How do they feel if you run your fingernail across them?  It's hard to tell things on my phone.

Perfectly smooth, nothing to catch a nail on.

Pete Whitstone wrote

I did try the "bolt the starter on and spin the TC" test. It was inconclusive, no noise was made like the noise in the videos, but the starter could only spin it about as fast as it does when starting the engine, I thought it would spin a lot faster without the drag of the engine on it.

That's the thing about most electric motors, 100% torque from 0 rpm.
They will turn the rpm they're wound for (as long as they get the required voltage) or they will melt down trying.
PMGR starters spin much faster, but are geared down to get enough torque from the smaller motor to turn the engine at a decent cranking speed.