Rattle and vibration - not typical - at idle and around 1350 rpm

[davlun]

Hi All,

This is on my newer to me idi diesel. This is my first diesel and why I cant say that I am the best at picking out things on the diesel engine, I can say that it sounds different than it did.

Had some work done to the suspension, brakes in front and thought something was loose, rattling. It sounds a bit like sheet metal vibrating at idle. If I give it any increase in rpm, no matter how tiny, the it goes away. A local mechanic who works on gas but has owned lots of fords, thinks it is normal for diesel to change sounds at times. To me, it would seem that there would be a baseline sound and then variances on that are something to be checked out.

More info. The vibration/rattle at idle is not constant. It varies from about 20-85% of the time and is best heard when crouching by the front tires. If you could picture the sound of a spoon rattling around on a piece of steel, that is kind of the sound. When driving, there is a vibration sound at about 1300-1400 rpm with a light pedal. If you give it a medium pedal, it is not heard at all. I first thought the vibration was the cow-catcher on the bumper as it is loose, but is not prone to tightening.

This is my first diesel, do not not have a mechanic and am having issues finding one locally that is recommended. Any thing I can do to self diagnose?

Thanks,

David

 

[BDCarrillo]

Feel around the firewall and fender wells for anything rattling. The cowl cover on one of mine acts similar to your issue and vibes at idle, then smoothes out above idle.

I've had another where the air cleaner jiggled an A/C line and transmitted some vibe noise

 

[LCAM-01XA]

The IDI transmissions have a stamped steel inspection plate at the bottom of the bellhousing, if that is loose it will make all sorts of horrible sounds. IIRC the bolts in the E4OD application took 10mm socket/wrench.

To test the cow-catcher wrap a piece of bungee cord around it, fish it thru the grille, the wrap it around the vertical bar of the radiator support that runs straight down from the hood latch. The extra tension provided by the bungee should put just enough pressure on the cow-catcher to hopefully shut it up.

 

[davlun]

So surprise, didnt even make it to the inspection port. I was looking in from the top and sides at the firewall, have some nice cracks there. Then I found what the shop was talking about (who was investigating some creaks/cracks when the plane for the front axle was different than the rear, like some specific driveways). They said it was the firewall flexing, looks like they should have said cracks. But they also said that it was better when they backed out bolts for left front fender, leaving some play. Seems that those have vibrated out as the two at the top near the firewall are gone as well as the two down below closer to the wheel.

But I may have two issues.

Today I started it to move the truck out to the street, put it in reverse, and it took a few for it to get going, acting like something wrong with trans like maybe the torque converter had to fill up...

Ugh, really need to find a good mechanic out here where I live. Will check the inspection port tonight. Thanks for the comments guys.

David

 

[LCAM-01XA]

Reverse on the E4OD tends to engage rather slow, nothing new there.

Cracks in the firewall are news to me, rad support yes that's kinda normal, but firewall should only have cracks around the clutch master cylinder which you obviously do not have... Any chance you can take pics of where the firewall cracks are?

 

[BDCarrillo]

On the torque converter... Check your fluid level. If you have an aftermarket cooler, consider bypassing the thermal valve (if it's a separate block, will have 4 hoses to it).

Otherwise, check pump output. You'll have to google that one, I don't remember the process/specs.

A severely lazy reverse is from low fluid, poor ounp output, or wear clearances in the clutch packs stacking up.

 

[davlun]

I did check the fluid in trans, it seems ok. I find it challenging to get the dipstick in and out of these without it seeming to fall back some as I have to reach so far back to reach the thing. I either have to be on a stool or standing on top of the tire to reach it.... checking pump output seems beyond my fledgling capabilities, but will google it. Would you say severe is 5 seconds, maybe a tad more?

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Attached is the picture of the cracks, it is not by the clutch which you rightly said I dont have, but in a seam up by the upper front door hinge on the driver side. There may be more that I cant see.

The inspection port for the trans is not loose, cant giggle it at all.

Thanks for the help.

 

[LCAM-01XA]

Yup, you stand on top of the tire to reach anything back there, get used to it. It's even more fun if truck is lifted Some military and offroad big cabover trucks actually have step-rings bolted to their wheels, held on by the lug nuts - gonna be hard to do that on a SRW domestic pickup with steel wheels that were never designed for such contraptions tho. But yeah, IDK how tall you are, but if you think it's hard for you to reach you should really see my better half try it - at 5'4" she doesn't have much of arms reach, so more often than not she just climbs up the bumper and on the rad support. Which, you having the same body style as ours, you know how much space there is to stand on top of that... Ninjas man, freakin ninjas!

The cracks you see are not cracks in the cab, they are cracks in the seam-sealer, and they're normal for a truck of that age, nothing to really worry about there.

Next up, pop the converter inspection pan from under the trans, check all four torque converter nuts. Unlikely to be the problem, but better safe than sorry.

After that, check your exhaust real good. Ours is a N/A and cracked right at one of the flanges for the manifolds. Aftermarket pipe was noticeably thinner than factory, hacked up a factory pipe to fix it. I realize you are turbocharged, but nevertheless worth inspecting the piping, especially near welds and other joints. Our issue was mostly caused by a missing hanger under the cab, the presence of an exhaust brake likely didn't help much either. So check your hangers.

 

[davlun]

Update, easy things first:
1) tapping around underneath, it was clear the cow catcher was making noise, it was unable to be tightened more, off it came, no change in anything
2) added bolts back to driver front fender, no change in anything
3) bungied the front grill, it was cracked and very loose, no change in anything
4) can really see anything obvious in exhaust, have to be obvious as I really have no idea what a crack looks like

So I am trying here, but my beginner skills are all but depleted. Going to the transmission inspection next, put that off as I am least confident about checking that.

In the interim, I uploaded a video so some of you diesel experts can hear things, above and below the car. Had my son sit in the car and slowly increase rpm from idle to about 15-1600. Maybe it helps. Pushing on the belts, they seem really tight, very little flexing.

At the end of the video you can hear the rattle that started this process. I also hear a tick sometimes when standing around. Dont have enough experience to know what is normal sounds yet.

http://youtu.be/uL8fJyqzclM

Thanks,

David

 

[davlun]

Bump for today. Thanks for all the help so far.

David

 

[snicklas]

OK, I listened to the video..... to me the engine sounds pretty good.

The noise in question at the end the me sounds like 2 pieces of metal rubbing together when the correct harmonic is achieved in these two parts. For Example, Dad and I collect IH Cub Cadet Garden Tractors, on one of mine a 1450 (14hp Single Cylinder Kohler and hydrostatic transmission) the seat pan to seat pan hinge will rattle at just a certain idle speed. When I start it, if I am not sitting on the seat, it will make the most hellatious noise..... you would think something was going to come apart. If I just bump the throttle lever and change the idle speed at all, the noise goes away. It took some time to find it........ It could be anything from the exhaust rubbing on something (frame, loose hanger, loose connection) to a loose bolt rattling in its hole. I have dealt with several of these types of noises on vehicles and equipment over the years. Even in my 03 Excursion, when the engine is cold and the idle is slightly different than the same speed warm idle, the far left side of the dash will vibrate just a bit. Once the engine warms up, the vibration is gone........ Sorry I can't help pin it down, but I would start crawling around the truck, and see where the sound is the loudest. Once you are in the area, I would start grabbing (as long as it's safe to grab) and see if the noise stops. This is how I found the seat pan, and dash noises on my stuff.........

 

[davlun]

Thank you for your suggestion, I will try to do some more hunting around and see what I find. It does change once the rpm changes slightly.

I saw your reply when I logged in back here to post an update. I met a gent who works on big rigs, he was kind enough to take a listen. He thinks the sound it is related to my vacuum pump, but by his own admission does not work on 'small diesels'. He based his opinion that it sounds like it is coming from that area, holding the house that exits the diaphragm for the vacuum pump it seems to be pulsing or vibrating, he did not think it should do that, but not positive, would need to find another idi like mine and feel the hose on that one. He seemed to think the vacuum pump was cycling which would explain the different sound at times. Does the vacuum pump cycle on and off? If so, what controls that?

He also noticed that at times the loose belt you can see in my video, seems to gather it's extra material on one side or another, when it is flapping on the bottom side of the belt, it looks like it is just touching the pulley on the vacuum pump. Is it possible for the two things to be happening at the same time at certain rpm's causing that change in tone what seemed to me to be a vibration?

Thanks all!

 

[snicklas]

The vacuum pump on these trucks is a diaphragm type pump just like a mechanical fuel pump. It does not cycle like an A/C Compressor or an electric vacuum pump, if the engine is running, it runs, just making vacuum. You may feel a pulse as the diaphragm cycles up and down.

The belt could "flop" at certain RPM. The alternator belt on the V-Belt IDI's loves to flop around, and if it is hitting something, I would think it could make a noise. The clearances in there on some of this stuff is tight. Is that belt "tight"....... I would look, because if it is hitting something, there should be some kind of witness marks, either on the belt, or on what it is hitting. I had a belt loose on my Jetta, and it wore a hole in one of the plastic covers on the engine. Noises like this can take some time to find......

 

[LCAM-01XA]

Oh oh, I know what it is!!!!

The vacuum pump has a metal clip on the back side, it's attached to the diaphragm pod but for the life of me I can't recall what it actually does. I mean other than sit there semi-loose, get into harmonics, and start vibrating and driving you nuts. Pull the pump off, flip it around, you'll see the stupid thing on the back side. Decide how you wanna silence it, then silence it

Been there done that, drove me nuts!!!

 

[davlun]

... Dad and I collect IH Cub Cadet Garden Tractors, on one of mine a 1450 (14hp Single Cylinder Kohler and hydrostatic transmission) ...

Interesting on the kohler engines. I have a k662 (I think) - never used really as it is attached to a generator that was purchased at surplus in the 60's and stored away. Never had gasoline in it until I purchased it and dont believe it has ever had an electrical load as there were no receptacles ore wiring installed in the box for that purpose on the genie. I had heard some tractors had kohlers in them but never had confirmation until now.

Thanks for the help, thought you might find that interesting...