Need Help with Harmonic balancer diagnosis

[Suburban Kelly]

Engine got louder like ten times not like exhaust leak loud but like the diesel noise

[Sundance]

How many miles?? You can do a visual inspection looking for distorted rubber and or gaps. When in doubt, change it out. It will kill your crank in short order.

[simple man]

Depending on the age of our vehicle, the balancer on your 6.5 should be "two part". I just replaced both of mine in the last 3 to 4 months. The main is is held on by a large single 1" bolt , but to get to that there is another one that has 5 or 6 bolts that are about 3/8" to 1/2" - only in metric size. This balancer / pulley will bolt on to the other one that I first described.

To check them you can do a visual, but will be rather difficult due to the location and other crap in your way. You should be able to use a small mirror and light to get a good look though. You would also want to remove the serpentine belt and get a good "feel" of the balancers to see if you feel any rocking motion or play. If I remember right - you can get the balancers from Oreilly Automotive for around $60.00 for the one and about $95 t0 $100 for the other. When my outer balancer / pulley went bad - it sounded like I had a rod knocking - so they are rather noisy in the fail mod.

Hope that helps :)

[Suburban Kelly]

I did the test of putting a rachet on the altenator and turned it. Supposedly if the HB is bad you can turn the pulley 1/2-3/4 in easyily. Now I'm a pretty stout guy but I could easyily turn the whole belt section pulleys and crank pulley many rotations.

I am now concerned that I have a broken crank. but the burb still runns really good and if I broke the crank wouldn't it really run bad.

Should the engine turn over that easy?

[Suburban Kelly]

I pulled the crank pulley and the rubber in it though dry rotted dit not seem that bad. It was still plyable and intacked. So I concentrated on the HB it self.

At first it did not seem like there was anything wrong the ribber looked good. I rotated teh motor over and found an are on the back side about an inch long where some of the rubber was missing. Now it looks just superficial as it only goes about 1/8" deep but I think I will replce them both and see if that does not help the problem.

What do you think.

This all started the other day when I accelerated hard to get out in front of some traffic. Not right away but about ten minutes later I noticed that the engine noise was like ten times louder than normal. Not like exhaust noise either. under mild or hard acceleration it would quite down and then come back when I was not accelrating.

[grancito]

Take a piece of hose and use it as a stethescope to listen to where the noise is coming from the engine. It will only get you close as diesels make lots of noise everywhere.

[torque454]

Sorry to say this but isnt it usually a rod or main bearing that makes alot of noise at idle, or sustained speed, but quiet while revving (accelerating)?? I had a buick that did that, it was a rod bearing. It didnt have the power it should have had tho, either. A loose torque converter or flexplate/flywheel bolt will make alot of noise like that too. That can sound like a rod knock.

[Bentt]

I had the a similiar noise this fall, at idle terrible noise coming from the front of the engine , also when shutting down the engine, horrible noise . When the engine was running over 1200 1400 rpm noise reduced substaintually. It turned out to be the crank shaft pully . Oddly enough the part from the supplier was labelled as the harmonic balancer but ordered as the front crank shaft pully. After advice from members on the forum I ordered a harmonic balancer which connents directly to the crank via a key and one bolt the crankshaft pully bolts to it via 5 or 6 bolts. Anyways once the crankshaft pully was changed noise disappeared truck runs great. I returned the first part ordered as a harmonic balancer. However i did pull off main balancer and inspected the key for wear and did replace on advice from a ss member. I don't imagine it would be pretty if that balancer spun on the crank should that key break. Good luck

[Suburban Kelly]

Well I got both of the new balancers installed today and fired up the burb. Noise still there so since it was still up on block I crawled under the truck and man it sounds like the crank is coming out the bottom of the pan.

So where do I go from here. I have spent $6000 on this motor in the past six months. Over heated and cracked heads, new heads, injectors, road side labor (really expensive). Add in the $1400 Power Package at Christmas and I'm buried in this thing. Besides The burb is in really good condition still, like new.

I'm thinking maybe tomorrow I'll drop the oil and look for metal. After that I guess I'll have to pull the motor. Man I'm not looking forward to that. One car garage no room full of motorcyles and other stuff.

Might have to sell the harley to afford to fix the burb. Any suggestions I would be open too

[grancito]

Don't put your head under the oil pan, a good engine will make you deaf. How is your oil pressure? A bad bearing will cause it to be low. To look for metal particles, cut the oil filter open and look in there.

[torque454]

I want to put the 80hp chip in my truck but after hearing this im kinda scared that ill screw up the engine. yikes.

[Suburban Kelly]

I tink it is main bearing so I am now looking for an engine

[Suburban Kelly]

Its not the chip its the driver. If I had not stomped the shit out of it turning tire and leaving the stop light like I did I probably would not be writing about this now.

But if you can't us it why have it

[torque454]

Thats my point. I dont know if i should buy it or not. If i cant use it... no need to have it and spend the money. Marine injectors, 4" exhaust, and an intercooler, #9 resistor... might be as far as i go. 40hp chip might be ok but man for the same price you can get the 80hp chip. Thats what bothers me about that.

[grancito]

I tink it is main bearing so I am now looking for an engine
A main bearing will not make a noise, only a rumble as the revs come up above idle, a big end bearing will rattle bad as the engine revs drop with no load, unless it is realy bad then will rattle bad with reving low load. Can be confused with piston slap, shrunk piston from over heating.

[torque454]

Yeah im kinda thinking rod bearing too. Seriously tho inspect the flex plate, and all the bolts holding the torque converter to the flexplate, as well as the flexplate to crankshaft bolts. Those can make some nasty noises too.