Now, for the biggy: KNOCK OR REVERBERATION that is scaring me.

[joe bleaux]

Folks, I have asked many questions and I hope that I am not a pest by doing so. It is the only way that I have to learn about this vehicle right now.

Anyway, this truck with 210k looks like a new one and I already love it (strange)but I hear a hollow sound that I cannot isolate even with a mechanic's stethoscope.

It sounds a bit like someone lightly hitting an empty barrel with a wooden mallet. I do see some play in the harmonic balancer and am going to buy one fast.

Could this possibly be exhaust sound into such a big exhaust pipe? I can lock the brakes and rev it up and I hear no rod knocking sounds and such.

Also, is it difficult to replace the front-seal when I replace the harmonic balancer? Should I replace the serpentine drive pulley, too?

Seems that I can't stop asking questions.

Thank you.

Joe

[joe bleaux]

Does anyone know about what I asked below?

Has anyone replaced their front-seal on a '98 6.5td?

Joe




Folks, I have asked many questions and I hope that I am not a pest by doing so. It is the only way that I have to learn about this vehicle right now.

Anyway, this truck with 210k looks like a new one and I already love it (strange)but I hear a hollow sound that I cannot isolate even with a mechanic's stethoscope.

It sounds a bit like someone lightly hitting an empty barrel with a wooden mallet. I do see some play in the harmonic balancer and am going to buy one fast.

Could this possibly be exhaust sound into such a big exhaust pipe? I can lock the brakes and rev it up and I hear no rod knocking sounds and such.

Also, is it difficult to replace the front-seal when I replace the harmonic balancer? Should I replace the serpentine drive pulley, too?

Seems that I can't stop asking questions.

Thank you.

Joe

[More Power]

Does anyone know about what I asked below?

Has anyone replaced their front-seal on a '98 6.5td?

Joe

A diesel engine will produce various sounds, mostly combustion rattle, that can vary throughout the year, depending on ambient temperature, fuel injection system performance and fuel quality.

In general, if you have to wonder about whether or not a particular sound might be a bad sound, it probably isn't. A bad mechanical sound will always be present.

A bad fuel injector can be eliminated as a cause of a knocking sound by loosening each injector fuel line fitting one at a time. Loosening the fitting will allow fuel to weep and that cylinder won't fire. If the knock disappears, you may have found a leaking injector.

Yes, I've replaced a couple front seals....

Jim

[Kennedy]

It sounds a bit like someone lightly hitting an empty barrel with a wooden mallet. I do see some play in the harmonic balancer and am going to buy one fast.

Also, is it difficult to replace the front-seal when I replace the harmonic balancer? Should I replace the serpentine drive pulley, too?

Seems that I can't stop asking questions.

Thank you.

Joe


If you can "see" play in the balancer you are probably seeing the crank pulley. If the rubber goes bad it will make hub to spoke contact and make noise.

Also, the vacuum pump can make noise if the bearings etc go bad.

[joe bleaux]

Thanks, Kennedy.

Are you saying that the play is the crank pulley and IS NORMAL? In other words, should one NOT see any wobble in the pulley/balancer?

Joe



If you can "see" play in the balancer you are probably seeing the crank pulley. If the rubber goes bad it will make hub to spoke contact and make noise.

Also, the vacuum pump can make noise if the bearings etc go bad.

[joe bleaux]

More Power, Thanks for the input.


I have a number of diesels including a 6.2 and am familiar with how they sound in their normal, rattle, clatter and such. I have not yet had time to 'crack' each injector but I can't discern any miss in idling or underway.

Sounds are hard to describe but this sounds pretty much as I described: a hollow sort of echo as a barrel being tapped lightly with a block of wood. It really bothers me with this being a new vehicle to me with 210k miles.

Have you changed a front-seal on a 6.5 and is it difficult?
I ASSume that when and if I change the harmonic balancer, is the time to do it.

Joe




A diesel engine will produce various sounds, mostly combustion rattle, that can vary throughout the year, depending on ambient temperature, fuel injection system performance and fuel quality.

In general, if you have to wonder about whether or not a particular sound might be a bad sound, it probably isn't. A bad mechanical sound will always be present.

A bad fuel injector can be eliminated as a cause of a knocking sound by loosening each injector fuel line fitting one at a time. Loosening the fitting will allow fuel to weep and that cylinder won't fire. If the knock disappears, you may have found a leaking injector.

Yes, I've replaced a couple front seals....

Jim

[DmaxMaverick]

Thanks, Kennedy.

Are you saying that the play is the crank pulley and IS NORMAL? In other words, should one NOT see any wobble in the pulley/balancer?

Joe

No. Not normal. If the balancer and/or rubber isolated pulley is bouncing around, replace them, before the crank follows suit.

[DmaxMaverick]

Changing the front seal isn't bad, at all. It is a good time to do it while doing the balancer. Unless you are planning on a facelift of the front engine components (water pump, etc), don't replace unless it's leaking or you have another reason to do it. Usually, if it isn't leaking, it won't. You can pull/replace the seal w/o removing the timing cover (with a good seal puller tool), but it's best to do it with the cover removed. It's just a standard steel/rubber ring type shaft seal. Not unlike any other SBC/BBC, but the cover is cast aluminum, vs. stamped steel.

[joe bleaux]

Righteo, DmaxMaverick.

I will get a seal puller tool and do the deed when I do the balancer. I am not driving the vehicle now and it is killing me since I bought it and drove it straight home.

Should I replace the pulley, as well?

Thanks for the info.

Joe.




Changing the front seal isn't bad, at all. It is a good time to do it while doing the balancer. Unless you are planning on a facelift of the front engine components (water pump, etc), don't replace unless it's leaking or you have another reason to do it. Usually, if it isn't leaking, it won't. You can pull/replace the seal w/o removing the timing cover (with a good seal puller tool), but it's best to do it with the cover removed. It's just a standard steel/rubber ring type shaft seal. Not unlike any other SBC/BBC, but the cover is cast aluminum, vs. stamped steel.

[DmaxMaverick]

If the pulley is original, I'd replace it. The rubber is likely in the same condition as any other of the same vintage on your truck. Better now than later. Conditions for a repair may not be favorable if/when it fails. "An ounce of prevention....", as it were.

[joe bleaux]

Okay, Dmax.

I didn't realize that the pulley had rubber, as well.

I agree about the "An ounce....."

Thanks.


Joe




If the pulley is original, I'd replace it. The rubber is likely in the same condition as any other of the same vintage on your truck. Better now than later. Conditions for a repair may not be favorable if/when it fails. "An ounce of prevention....", as it were.

[DmaxMaverick]

The 98 should have the isolator pulley. Check to be sure (it may have been de-evolved). Remove/loosen the belt and wiggle the pulley. If the pulley wiggles and the hub doesn't, it's an isolator. If it wiggles a lot, it's on borrowed time, and probably the source of much of your issue.

[joe bleaux]

Good info, Dmax. I will check it to find out.

Regardless, do you know who may sell the isolator pulley and harmonic balancer? I doubt the dealers carry anything that old. I will check tomorrow.

I don't want the fluidamper - too many bucks.

Joe and thanks, as usual.



The 98 should have the isolator pulley. Check to be sure (it may have been de-evolved). Remove/loosen the belt and wiggle the pulley. If the pulley wiggles and the hub doesn't, it's an isolator. If it wiggles a lot, it's on borrowed time, and probably the source of much of your issue.

[DmaxMaverick]

The dealer still carries them, but for a price somewhere in the neighborhood of your first born, or on sale for appendages. gmpartsdirect.com and/or rockauto.com will have the best dealer stock prices. If you shop them and don't find the part listed, contact them for your application and pricing.

Shop TDP Advertisers (http://www.thedieselpage.com/vendors/main.htm) for your best options regarding prices and customer service.

[joe bleaux]

Well, Dmax,

I found a company selling the balancer and he says he bought a pallet load of them a few years ago from General Motors Service Parts Organization.

A pallet load? I wonder if they could possibly be rejects.

Somewhere, perhaps here, I read about after market balancers not holding up. Do you know anything about that?


Thanks.

Joe


The dealer still carries them, but for a price somewhere in the neighborhood of your first born, or on sale for appendages. gmpartsdirect.com and/or rockauto.com will have the best dealer stock prices. If you shop them and don't find the part listed, contact them for your application and pricing.

Shop TDP Advertisers (http://www.thedieselpage.com/vendors/main.htm) for your best options regarding prices and customer service.

[DmaxMaverick]

GM doesn't sell "rejects", so they are GM NOS, take offs (slightly used), recycled (well used), or he is lying about the GM parts source.

Beyond that, you got me.... I'd have to see it/them.

[joe bleaux]

I'm confused, Dmax.

He provided a number: " THE GM PART NUMBER OF THESE IS 12557345".

It confused me when you said that he could be lying. Are you saying that he may be lying about that he got them from the GM Parts Service Org.? Could you clarify?

Also, exactly what is a "down-pipe"?

Tnx.

Joe


GM doesn't sell "rejects", so they are GM NOS, take offs (slightly used), recycled (well used), or he is lying about the GM parts source.

Beyond that, you got me.... I'd have to see it/them.

[DmaxMaverick]

The downpipe is the pipe connecting the turbo to your exhaust pipe. It bolts or clamps to the turbo, and conveys exhaust gasses exiting the turbo.

I didn't mean to imply he was lying. Just one possibility according to your recall of his statement. Having a GM part # does in no way guarantee an authentic part. Many "counterfeit" knock-off parts sport the OEM #, which is what makes it "counterfeit". Those balancers may very well be on the up and up and perfectly fine. I'm just advising caution. I'd need more info on the supplier to whom you are referring to comment further or come to a conclusion. GMSPO is the supplier of OEM GM parts to dealers, outfitters and authorized GM remanufacturers, and normally doesn't sell to individuals or jobbers. Just curious, but not at all impossible.

[joe bleaux]

I have been 'around the block', too many times to not be cautious. But, at some point, there is not much that you can do when buying from an individual, whom you have no experience with.

I understand the term 'down-pipe', now.

Would you put an after-market balancer/pulley on your gear?

Tnx

Joe


The downpipe is the pipe connecting the turbo to your exhaust pipe. It bolts or clamps to the turbo, and conveys exhaust gasses exiting the turbo.

I didn't mean to imply he was lying. Just one possibility according to your recall of his statement. Having a GM part # does in no way guarantee an authentic part. Many "counterfeit" knock-off parts sport the OEM #, which is what makes it "counterfeit". Those balancers may very well be on the up and up and perfectly fine. I'm just advising caution. I'd need more info on the supplier to whom you are referring to comment further or come to a conclusion. GMSPO is the supplier of OEM GM parts to dealers, outfitters and authorized GM remanufacturers, and normally doesn't sell to individuals or jobbers. Just curious, but not at all impossible.

[DmaxMaverick]

......Would you put an after-market balancer/pulley on your gear?

Tnx

Joe


Yes and no. An aftermarket balancer, such as the Fluidamper, yes. But not a no-name OEM-type replacement. OEM for the pulley, as well. I've seen too much inferior stuff of different brands/mfg. The OEM parts are what they are, and are somewhat predictable. That doesn't apply to all parts, but the parts in question. That's my opinion, according to my experience. You may hear of some aftermarket balancers/pulleys that do fine, but it's been my experience those are the exception, not the rule.

[Scooby]

I just replaced the pulley, damper, and seal a few months ago. None of it hard at all. Use the right puller to pull the damper back on, or a long piece of all thread so as to not damage the damper bolt. The pulley I got from the dealer. Part # 12557345 , out the door at 197.42. Ouch, I know. I read too much on here about aftermarket junk, so I went to the dealer. I wont tell you what I paid for the Fluidamper, but I will say it runs nice and smooth now. LOL !!! My old damper was still OK, but I just hate what I read on here about crank failure, so I made my choice.
Rick

[joe bleaux]

Good info, Scobby. Thanks.

I have a puller shaped like a duck's foot, so to speak.

Did you take the front-cover or timing chain cover off in order to replace the seal?

Also, this '98 6.5td has 210k on it. I wonder if it is time to change the timing chain? I am not rich and cannot replace parts willy-nilly but, I don't have money for big problems later.

Yes, I priced the Fluidamper and WHEW!

Joe




I just replaced the pulley, damper, and seal a few months ago. None of it hard at all. Use the right puller to pull the damper back on, or a long piece of all thread so as to not damage the damper bolt. The pulley I got from the dealer. Part # 12557345 , out the door at 197.42. Ouch, I know. I read too much on here about aftermarket junk, so I went to the dealer. I wont tell you what I paid for the Fluidamper, but I will say it runs nice and smooth now. LOL !!! My old damper was still OK, but I just hate what I read on here about crank failure, so I made my choice.
Rick

[Scooby]

I didnt remove the timing cover to replace the seal. I wrapped the crank nose with a rag, and carefully used a large screwdriver and thin alignment bar to work the seal out. I have used a punch to bend in one side of the seal before, by pushing it toward the crank, but I hate doing that, so I always try prying out at two points first.
As for the timing chain, it's your call. I didnt do mine (145000 miles), as the truck runs good, and I think I would do a bunch of stuff if I did get into the chain- like possibly going to gears, and doing the cooling upgrade "while I was in there" . I didnt have time (or $$) to do all that when my pulley rubber failed, so that's all I did. :)