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I need some help in trying to identify the cause of an engine/valvetrain noise. The engine has made the the noise for as long as I have owned it (I have put about ~2,000mi on it) but I think it's getting worse now that I am driving the truck a lot more. It's beginning to irritate me that my valve train is louder than the flowmaster. The truck runs very good otherwise and does not burn any oil!

 

89 Renix 4.0L 127,000mi close to 1,000 miles on 15w40 rotella t Wix filter oil change.

 

Symptoms:

 

It sounds kind of marble like, definitely not a knock or tick.

 

Varies directly with engine speed.

 

Most evident around 1200-1500rpm.

 

Not as noticeable at idle or above 2000rpm. I am sure it is still there but it's being drowned out by the exhaust.

 

Does not go away under load.

 

Sometimes although it hasn't done it for a while, when you start it up first thing in the morning, it'll make a loud chuh chuh chuh sound for a second or two. Related? :hmm:

 

:help: Lifter(s)? Not getting oil to a certain part of head? Piston slap?

 

I can try to take a video of it tomorrow but I don't know how good of audio quality it'll be.

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Ok, I did some poking around with a screwdriver. It didn't really help locate the noise but, by putting my ear around various locations, I think the noise is coming from a couple different locations. I think it is originating from the rocker arm area of cylinder number 2 and like cylinders 5 and 6. It's really hard to pin point it. When you put the screwdriver on say the valve cover, you just hear a constant vibration from the engine running. You can't hear the marbely noise (is that even a word) . Put when you put on the injectors you can hear them ticking away. Cool!

 

So what kind of noise can the rocker arms produce? And why? What kind of damage/ wear could this cause?

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I've never heard of the word "marbley" but for the sake of this diagnosis we're gonna go with it. :rotf:

 

I'm assuming by "marbely" your talking about the way a hand full of marbles sounds when rolled around in your hand. Right?

 

First, I've never heard a valve train make any kind of a "marbely" sound. Tick tick .... yes. And even a low "grumbley" sound when heard through a scope or screw driver as they all work together but never a loud enough marbely sound to be audible by the naked ear.

 

Noises have a funny way of jumping around in an engine compartment. OK, maybe not jumping around but sounding like their coming from somewhere other than where they actually are.

 

By your "marbely" description, I'm thinkin Idler pulley. Remove the belt and check the idler pulley bearing.

 

Quick test to eliminate other accessory bearings ........ While the belt is off start the engine for a few seconds and see if the noise in still there. If no noise, you now know its something the belt turns. Turn all the pulleys by hand and see if they feel smooth. Check for excessive play too. (try to wiggle um back and fourth or up and down)

 

If none of the above, try listening down around the distributor and on the front of the engine near the timing chain.

 

BTW, for listening to the engine a pc of dowel rod or even a cut off broom stick works too. Unless you have a screw driver thats 2 feet long, they can also give you a longer reach. I use a pc of 3/8" dowel rod thats about 2 feet long. Like the handle of a screw driver or a broom stick, I rounded off the end so its a little easier on my ear. Works great.

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I've never heard of the word "marbley" but for the sake of this diagnosis we're gonna go with it. :rotf:

 

I'm assuming by "marbely" your talking about the way a hand full of marbles sounds when rolled around in your hand. Right?

 

First, I've never heard a valve train make any kind of a "marbely" sound. Tick tick .... yes. And even a low "grumbley" sound when heard through a scope or screw driver as they all work together but never a loud enough marbely sound to be audible by the naked ear.

 

Noises have a funny way of jumping around in an engine compartment. OK, maybe not jumping around but sounding like their coming from somewhere other than where they actually are.

 

By your "marbely" description, I'm thinkin Idler pulley. Remove the belt and check the idler pulley bearing.

 

Quick test to eliminate other accessory bearings ........ While the belt is off start the engine for a few seconds and see if the noise in still there. If no noise, you now know its something the belt turns. Turn all the pulleys by hand and see if they feel smooth. Check for excessive play too. (try to wiggle um back and fourth or up and down)

 

 

If none of the above, try listening down around the distributor and on the front of the engine near the timing chain.

 

BTW, for listening to the engine a pc of dowel rod or even a cut off broom stick works too. Unless you have a screw driver thats 2 feet long, they can also give you a longer reach. I use a pc of 3/8" dowel rod thats about 2 feet long. Like the handle of a screw driver or a broom stick, I rounded off the end so its a little easier on my ear. Works great.

 

What I mean by marbley is that it is more of a rattle or tapping sound than a tick or knock. Sounds sorta like marbles contacting each other. You know the sound a computer hard drive make when it's loading something, it's kinda like that. It's hard to describe, hopefully a video will help.

 

It's not the idler pulley bearing, water pump, power steering, alternator or ac. I already checked those trying to diagnose something else.

 

I am really thinking it's valve train related. When I put my ear right above the valve cover over cylinder one you could a regular tick tick tick, cylinder number 2: much louder and more marble like. Cylinders 3 and 4, same regular tick tick tick. Cylinder 5 or 6, it's hard to tell, is also loud like number 2.

 

But if you stick the screwdriver one the valve cover above the different cylinders they all sound the same, just like a constant engine hum. :???:

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OK, although the noise itself is constant, does it have a constant rhythm? Or is it more sporadic like your description of a loading hard drive? Without a constant rhythm leads me to think its more of a rattle.

If you pretty certain its in the valve train, pull the valve cover and see if there's something loose or rattling around on top of one of the rockers. If there's nothing visible and although its gonna make an oily mess, start it up with the valve cover off and try to pin point the noise.

 

(some rags laid on top of the intake and along the other side of the head will help catch some of the oily mess)

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How's your oil pressure? If the noise is centered in the valve train the top end might be starving for oil.

Oil pressure reads high. 75psi at cold idle 40 psi hot idle. 70psi at highway speeds. I have not verified with mechanical gauge.

PS: The new diode and rewired aux fan are working great.

 

OK, although the noise itself is constant, does it have a constant rhythm? Or is it more sporadic like your description of a loading hard drive? Without a constant rhythm leads me to think its more of a rattle.

If you pretty certain its in the valve train, pull the valve cover and see if there's something loose or rattling around on top of one of the rockers. If there's nothing visible and although its gonna make an oily mess, start it up with the valve cover off and try to pin point the noise.

 

(some rags laid on top of the intake and along the other side of the head will help catch some of the oily mess)

 

It's not sporadic like the hard drive, it just makes similar sound.

 

 

Valve cover is coming off. I will probably do it this weekend when I drive home. I might be able to work on it sometime earlier this week but the school my will probably get a little irritated if I leave an oil slick in their parking lot. We'll see.

 

What is the best valve cover gasket to get? RTV needed?

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Update.

 

I pulled the valve cover off and the gasket was in perfect shape, the inside of the valve cover looked absolutely brand new no sludge what so ever. All rocker arms appeared to be functioning properly. No blocked oil passages, oil flowing nicely, no broken springs, no bent push rods, etc.

 

I now think the noise is from a lifter or two. Other wise I don't know. :dunno:

 

I did not take a video because I think it would have had too poor of audio quality to really here the noise. The noise is not really that loud it just kind of annoying.

 

It looks like you need to remove the head to get to the lifters. Is that the case? I think I will live with it for a while. Maybe I'll try synthetic rotella next oil change.

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  • 1 month later...

So I finally got a mechanical oil pressure gauge and here is what I found:

 

Temp RPM Pressure

 

120°ish 900-950 rpm 50-60 psi

 

210° 900-950 rpm 40-45 psi

 

210° 750 rpm 35 psi

 

210° 2000 rpm 60 psi

 

210° 3000 rpm 62 psi

 

Oil: Rotella T6 Synthetic 5w-40

 

These numbers are fairly consistent with the readings the gauge gives on the dash. The mechanical one reads just slightly lower across the board.

 

What do you guys think? The noise is still apparent and these readings seem high to me :dunno:

 

Clogged oil passage? -What I don't like about that theory is that I am pretty sure that this truck has had the oil changed religiously every 3,000 miles for it's entire life and when I pulled the rocker cover it looked absolutely mint.

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I don't see anything wrong with those oil pressure numbers. My stroker numbers are slightly higher than that, and it's been going strong for about 12K miles now. I do have a Hesco HO oil pump in it though. I wouldn't worry about it in your case.

 

I have noticed that valve train noise is quieter when I use dino oil. My favorite is Chevron Delo 400 15W40 diesel oil. Been using it for years in all my junk.

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I don't see anything wrong with those oil pressure numbers. My stroker numbers are slightly higher than that, and it's been going strong for about 12K miles now. I do have a Hesco HO oil pump in it though. I wouldn't worry about it in your case.

 

What about the fact that this engine has close to 130,000 miles on it?

 

I have noticed that valve train noise is quieter when I use dino oil. My favorite is Chevron Delo 400 15W40 diesel oil. Been using it for years in all my junk.

 

I will give Delo a try next oil change, I've heard others say that it is of quality as well.

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It sounds kind of like both of my 4.0's. :D Really though, I have seen worn water pumps where that the vane will make contact with the housing and make a rattle........ without leaking. :fs1:

 

It doesn't sound like the other 4.0s I've heard. The water pump is new.

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