This Noise

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
The video doesn’t allow you to hear how it makes a ringing sound. But if I go with this theory, I would have to assume the belt is maybe snapping off the ridges on the fan pulley, and ringing it like a bell. That pulley does echo when you knock on it, so I suppose it is possible.

What can be done to fix this?
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Not the belt. The belt does chirp some when cold, but it is a different sound. Putting water on the running belt, and taking the belt off does not make the sound go away.

My theory now is that something is not quite right under the front cover. But the sound does seem to go away when the engine is revved at all.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Yeah, I have one. The only place I hear anything that sounds like it could be what I'm trying to find, is coming from the water pump/thermostat.

The rest of the engine is what I would call normal noise. This one place I get a loud ticking that seems to be the same rhythm as the ringing I hear, as if listening through the stethoscope changes the quality of the noise, but it may be the same noise. Know what I mean?

Anyway, if it is the water pump, I suppose it could be loose, and the blade is knocking. But the loudest tick I hear (through stethoscope) is at the thermostat housing.

I drove it a bit yesterday in the back yard to haul some of the trees I've cut down, it seems nice and quiet other than the ringing.
 

Roverman2010

Well-known member
Maybe you have super power hearing and you are hearing the jiggler valve fitted on the thermostat, lol

give it a rest and drive it. If you keep listening for strange noises you will hear them. As the great Stephen King said
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
I'm trying. I drove it today. It seems nice and smooth while driving, only makes the noise at or below about 1100 rpm.
 

Napalm00

Technical Excellence Contributor
I had a phantom noise in my truck for years that would sound like ringing when it idle and just above it. It turned out to be the e-brake cable bracket.

The e-brake cable bracket has a slot in the end for the cable to pass through. It's long and almost resembles a tuning fork.

When I was at idle or just above it the engine vibration would make the e-brake cable bracket sing or ring. One day while sitting in the truck I pulled up the handbrake and noticed that the noise stopped.

Eureka!
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
I'm almost certain it is coming out of front of engine.



Do any of you hear it on the video??? Even with headphones on?
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Friend of mine who has not seen the car in real life, not a Rover guy, just commented on the video. He mentioned that it sounds just like I said it did -- like knocking on a ceramic bowl.
 

Mud Ruts

Well-known member
So this started after you adjusted the valves and timing?
The timing sounds a bit retarded.
Does it blow any white smoke when cold?
What are the egt?s When you hear the noise?
What brand of diesel are you running?
How is your pump tuned?

I’m going to say that the fan shaft bearings are bad in the front cover. Because they all are in every 300 I see.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
So this started after you adjusted the valves and timing?
The timing sounds a bit retarded.
Does it blow any white smoke when cold?
What are the egt?s When you hear the noise?
What brand of diesel are you running?
How is your pump tuned?

I?m going to say that the fan shaft bearings are bad in the front cover. Because they all are in every 300 I see.


No, I've heard it off and on for a long time. But it could be that it is getting louder, hard to tell.
Did blow white smoke till I advanced the pump timing.
EGTs have never been above 1150, and I'm pretty sure they actually went down when I advanced the timing. I live on a hill, so I watch them climb every time I come home. They are typically 50-75 degrees lower now.
Diesel is usually B20 from Shell, but it is not their brand.
Pump is the pump, not tuned that I know of.


Good idea on the bearing. I think it is something along those lines, the water pump, or a loose stud holding the rocker shaft -- which I'm going to check for this weekend.
 

rocky

NAS-ROW Addict
Also, I have to admit that I ran the truck for a minute without the belt in place to see if the noise was still there -- it was.

Not the belt. The belt does chirp some when cold, but it is a different sound. Putting water on the running belt, and taking the belt off does not make the sound go away.

My theory now is that something is not quite right under the front cover. But the sound does seem to go away when the engine is revved at all.

The noise could just be concealed by the rising sound of the engine. We've eliminated the Serp and the accessories it drives.

Its getting closer to removing the front cover. Before you do that, try removing the fan and viscous coupling. I doubt the fan is wobbling on the WP shaft and catching the shroud or worse, the radiator. Unlikely, but worth trying before we pull the WP and front cover.

It really does sound like someone tapping a window with a coin....
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Yes, on the video the sound as you describe is what I'm referring to. In real life, it's like knocking a spoon on an empty ceramic cereal bowl. But you are identifying the same sound.

There is no fan or viscous coupling, just the blank pulley.

Before I open the front cover, I'm going to double check that the rocker shaft is properly seated. I would think this would cause other issues as well, but in two places I've seen people mention a 'ringing' type of knock that had to do with a securing bolt being loose or broken.
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
I've just spent the last few hours carefully checking everything I can think of. I opened the valve cover, looked for anything that might be knocking there. I adjusted the valves. Got the engine nice and warm, and I'm pretty sure I narrowed it down to coming from #1 piston. I was hearing it through the thermostat, but when I took the black cover off the top of the engine, I think it may have allowed me to hear what was actually happening. I got another video. You must be able to hear this noise, right? This can't be normal.

I know everyone says (not just here) to just drive it, but I can't help but think it is maybe getting worse now.

https://flic.kr/p/GVsTAc
 

RBBailey

NAS-ROW Addict
Callsign: KF7KFZ
Today, I adjusted the valves three times. I had done this a few months ago, and maybe that's when I started noticing the noise getting louder. So this evening I purposefully adjusted too tightly, ran it for a few minutes to see if there was any change. This may have caused it to get louder.

I let it cool down, then adjusted just the first two valves to be too loose. This might have quieted it down just a bit, but it's hard to say. I try to dismiss my bias by listening in different circumstances, etc...

After letting it cool down again, I adjusted all of the valves with a 0.010 blade to where I thought it was probably just a bit too tight, then measured with 0.008 to check, and I think I got some more consistent results.

The engine noise at idle is a tiny bit louder than it has been, but it is louder exactly as expected -- with a bit more diesel clatter. It's a nice, even pitter-patter. It sounds just like I think a 300Tdi should. But the ringing sound did not go away. I think it may be diminished a bit, back to the levels it was over the fall and winter.

Since it is 11:30 at night, I only ran it for a few minutes, then drove it about a 1/4 mile just to spin the turbo up, and make sure the temp gauge moved a bit. The knocking noise did seem to be a little more under control after the last valve adjustment. It wasn't as harsh.

I don't think this fixed the issue. But I think maybe having the valves adjusted better might have minimized it enough that I can drive it to Ship's. I might drive it to work in the morning to get a fresh perspective on what I'm hearing, since I think it is louder once warmed up.

I think it is piston slap. Gee, I hope my wife's Merc gets out of the shop soon!
 
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