Strange engine noises

[kyle_in_rure]

Hello all,

Have recently noticed two unfamiliar noises coming from the engine. When it is cold, I hear what I could best describe as a "tapping" sound. It's present at idle and increases with acceleration but goes away totally once it warms up. It's not incredibly loud but I can hear it in the cab.

The second sound also is somewhat like a tapping or clicking. This happens between 2000-3500 RPMs and it reminds me of a Diesel engine. It only happens maybe twice a week or so. Any suggestions on what may be causing this?

It's a 97 EB 4.6. With 220K miles. I use valvoline maxlife 5w20 synthetic. It leaks a about a quart every 1000 miles but I keep it topped off.

Some history:
I was throwing an O2 sensor code over the summer but I cleaned out the throttle body and it never threw another code. The engine also overheated back in August after blowing a heater hose. But there's no head gasket leak.

New plugs and wires at 170K

Thanks all.

 

[stamp11127]

The tapping you hear is from metal to metal contact inside the engine. This occurs when there isn't any oil between the parts and/or the clearance between them is excessive.
The cams rotate at half the speed of the crank so the frequency of tapping can help locate the area that it is coming from.
You may also have an exhaust leak that will vanish when the exhaust system is hot. I woild rule that out first.
If you could post a video that would help the members to determine the cause. Escpecially the diesel sound you mentionedm

 

[kyle_in_rure]

Ok. I will do that shortly when I can get a friend to help me so can video from under the hood.

I forgot to mention the firs "tapping" sound occurs at idle speed but only when the truck is in gear. I can't hear it in park or neutral

 

[Snag]

Stamp is correct. At a glance it sounds like insufficient oil or exhaust manifold, both common problems on these engines. The exhaust manifold is not life threatening but the oil tap certainly is. I would dig into the tick sooner then later as the oiling problem will likely kill your engine, or at least create some very expensive repairs.
Your engine is the first gen so arguably a better engine then the next series but some problems are common to both. You might also want to listen to the front of the engine as well because the timing chain tensioner is also a known failure problem creating ticking. At 220k miles the tensioners are certainly a possibility and should be replaced with the rest of the timing components. And at 220k replace the oil pump with a Melling unit, its right under the lower timing chain crank gear.

Good luck

 

[kyle_in_rure]

I'm probably an idiot but is there an easy way to upload a video file here ?

 

[stamp11127]

Put it on a hosting site such as youtube then link to it.

 

[docraymund]

Most likely the noise you hear when the engine is cold is piston slap. Not much of a concern. The second noise would be coming from a loose piston pin or worn connecting rod bearings.

 

[kyle_in_rure]

Here is the first sound it's making. Now that I've poked around a bit it sounds like it's coming from the bottom of the engine....maybe the transmission?

Sorry it cut off early. I ran out of memory. When I get someone else who can keep the brake on while I poke around I may post another video. It increases with acceleration and only makes that sound when it's in gear.

 

[stamp11127]

Sounds like a rod knock to me.

 

[kyle_in_rure]

Hmm. What is strange to me is that it goes away totally once warmed up.

Would a knocking rod keep making noise ?

 

[stamp11127]

All the rods I've heard do keep making the noise when running. But, you still have an issue that if left alone will let you know exactly what is wrong when it fails.
If you have a mechanic's stethoscope it would be advisable to try and locate where the noise is coming from or you could bite the bullet and drop the oil pan & inspect the rods.

 

[docraymund]

One way to confirm worn rod bearings is to do the screwdriver test. Remove a spark plug and raise the piston to TDC. Then lower the piston slightly. Get your long screwdriver and push down on the piston. If you feel a "give" that's a positive sign.

 

[Snag]

Wow, couldn't get a good listen but at a glance I would say rod knock. At 220k I think the engine is about clapped out, especially burning a quart every 1k miles and overheating it. Overheating any engine really takes its toll on many different parts of the engine. Like Stamp says, if not corrected you might soon see the problem.
Sounds like the low oil pressure syndrome these engines are known for "could" be part of the problem. The fix is time consuming and expensive. New timing chain assembly (since you are going that deep) and an oil pump. Short of that you might try a heavier grade oil. Also using a real oil pressure gauge would give you some indication of oil pressure. Also suggested is taking the pan off. Its a PITA but another good place to start your search. I would guess bearings well worn. Bad/warn bearings is the start of many high mileage engine oil control problems.
good luck

Edit,
also sounds like it could be dry start. Make sure you are using oil filters that have the drain back feature like the Motorcraft FL-820S. That and new oil maybe a little heavier like the 5-30 or 5-40 might get you some time

 

[rjdelp7]

Hello, Good news and bad news. I had the same issue on 2000 XLT 4.6. It was broken exhaust manifold studs. When the engine heats up, the metal expands enough to seal it. The more more studs break the worse it gets. Ford upgraded the studs to stop this issue. It is a expensive job, around $500 a side. The manifolds are probably shot, with that many miles and should be changed. I have heard people doing it, but it can be tough, if studs break in head(nightmare time). I had mine done with new parts for around $1150. That is with no tapped studs to remove. Driving with it making that noise, will probably be ok. I drove mine for over a year, until it I got sick of hearing it.

 

[detailer03]

if its coming from the bottom, yes, rod or main bearing, if the torque converter is going bad it might make a tapping or knocking noise, pick up one of the auto stethascopes from the auto parts store. it might pinpoint the noise, also wrist pins might make some ticking sounds also;
How old is the oil? is it dino or synthetic, are you using the correct quality oil filter?
How many miles on the engine?

 

[1955moose]

Lower end noises are heavy and slower than a upper end ticking or clacking, due to the speed of the crankshaft. The other guys are probably right as to your impending doom. You might try just for ha ha's, to switch out your oil with a heavier say 10/30 or 10/40 diesel oil like delo, or equivalent, along with a Ford filter. Normally I'd say 20/50 weight but you live in Tennessee where it gets down below 32 degrees. Some of our forum members have had good luck with other noise suppression on theirs using this oil. If it doesn't work, your no worse off. I'd be leery of any crankcase additives, they might make your problem worse. Save your nickels, you'll need them for another motor/SUV. Let us know what happens.


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