Possible harmonic issue - Should I stop NOW?

[MarkMorissette]

Heya everyone - I'm new here - looked like a great place to pickup knowledge on my new truck. I just picked up a '97 crew cab dually with the 6.5TD yesterday.

All is well but I immediately noticed that there was a noticable rattle audible from the front of the truck when it was running. Sure enough the more I looked the more I realized that the pulley on the front of the harmonic balancer is indeed in need of service - the rubber is toast.

The original owner had it looked at and his mechanic had said that it was a bad bearing in the AC compressor.

Now, I fully intend on fixing this ASAP, but I was planning on taking it approximately 150 miles round trip tomorrow to pickup my trailer - 21' at about ~3500Lbs. (Barely a load for the truck...)

Anyhow, given how much I've been reading on the harmonic balancer issue I'm now a little concerned about making this trip and am wondering if I should go with my other tow vehicle instead and leave the truck at home until I get the parts and get the job completed?

Before I joined I thought I spotted an article specifically on the harmonic issue but now that I've joined I can't seem to locate it.

Either way, all advise/suggestions appreciated.

Thanks

[More Power]

Welcome to the board!

If either the crank pulley or harmonic damper are toast, you'd do well not to run the engine till the bad part is replaced. Not even a little...

The harmonic damper and crank pulley have been discussed many times here in this forum. A search should turn up a bunch of reading... :)

Jim

[MarkMorissette]

Thanks Jim - I've decided to take my other vehicle for the RV pickup tomorrow night to pickup the trailer and leave the truck in the driveway - I expect to have the parts (new harmonic balancer and pulley assembly) by Tuesday or Wednesday and will do the job then.

I'll have to drive it about 10 miles to the location the work will be done, but I don't have much option there - I'll keep the revs low and nurse it along.

I did do a search and found many posts on the subject but many focused on teh problem, not the immediate severity issues - and I'm not sure how "bad" mine is by the standards many others hold.

I am hearing it, and it is noticable when inspected, so I'll assume I'm nearing the worse end of the scale though.

Am I correct in the fact that there was indeed a fairly in depth "How to" article on the site somewhere that deals the HB issue on the 6.5TD? As I mentioned, I was almost *sure* I saw it here somewhere (but behind the members-only area) before I joined, but now I can't seem to locate it.

Thanks

[More Power]

but I don't have much option there - I'll keep the revs low and nurse it along.

Most crank failures I've heard about occurred at low speeds and engine rpms. Depending on the harmonic order, the highest amplitude order can occur at low rpm.

If your damper was the biggest issue, I'd say not to run the engine or drive the truck at all. It's still a risk with a bad pulley, but there may not be an option if you're not equipped to R&R the part yourself. The pulley is pretty easy to replace....

We've produced a couple of indepth articles about the damper and pulleys, beginning in 2000 and another a couple years later. These articles were designed to alert owners to the potential problems that might develop and show what to look for. I don't think those older articles are online. However, I'm working on a brand new article that again discusses the problem, shows what to look for and introduces everyone to the Fluidampr. It'll be on the site sometime before mid September. :) In the meantime, I know we've discussed this issue many times here in this 6.5L Turbo Diesel forum, and I have posted pics of some of the problems.

Jim

[MarkMorissette]

I'll be doing the job myself. Right now I'm 90% sure that the majority of the noise is coming from the pully itself, although I'll admit that I'm not 100% sure how to diagnose the harmonic ballancer at this point.

What I do know is that there's no documented history of the recommended replacement having occured at the 100,000 mile mark, so for the $100 involved for the replacement, I'm not sure it's worth risking.

Thanks for the pointers on things though - perhaps we'd be better to bring the tools to the truck as opposed to the truck to the tools. ;-)

[More Power]

Once the pulley has been removed, take a good long look at the rubber layer between the inner hub and outer ring of the damper - both the front side and the rear. The rubber layer should be uniform all the way around, there should not be any areas where the rubber pushes out or in, there shouldn't be any chunks missing and the rubber shouldn't be cracked. The article I'm working on will include some good close-up pics that typify these sorts of problems. The actual damper used in the photos was removed from a 6.2 that suffered a broken crankshaft.

Jim

[MarkMorissette]

Excellent, thanks. I'm pretty confident my membership here has potentially paid for itself already. :)

I was searching the forums and reading up as I was responding here and did finally find that article I was looking for on the topic:

http://www.thedieselpage.com/members/features/cranks.htm

Not as in depth as the one you mention you are writing, but usefull none the less, and it scared the pants off me on the crank issue. I'm confident that if the original owner hadn't discovered this issue soon (as it was initially diagnosed as an A/C bearing, as I mentioned) he'd be looking at a trashed 6.5 really soon.

I've made arrangements for the "tools to come to the truck" instead of the other way around. In the meantime, it won't be run whatsoever.

Is there any FAQ / HowTo's on the full pulley/harmonic balancer replacement anywhere here? Again, I'm searching and reading, but sometimes a direct nudge in the right direction is appreciated as a newbie.

Thx

[More Power]

Remove the serpentine belt, put the truck on a lift or on ramps, then drop the aluminum skid plate behind the front bumper. You'll have access to the damper/pulley. Alternately, you could remove the top half of the fan shroud and remove the fan & fan-clutch. Place a piece of cardboard over the radiator to help prevent damage.

When re-installing, the 4 pulley bolts are torqued to 35 ft-lbs. Clean off any accumulated dirt & trash so the pulley can sit squarely on the damper.

The damper.... You can remove the damper bolt using an air wrench. A breaker bar will also work, but you'll need to drop the trans bellhousing cover so you can keep the crank from turning by wedging a prybar between the block and a hole in the flexplate.

You'll need a puller to get the old damper off, and a damper installer makes installation a lot easier. It's easy to strip the threads in the end of the crank if you attempt to run the damper onto the crank snout using the damper bolt. You can make a damper installer by buying a metric bolt that fits the crank, weld on a piece of all-thread onto that new bolt you bought, then use a nut on the all-thread to get the damper fully seated on the crank. Once the damper is on, remove your installer, then tighten the damper bolt to 200 ft-lbs. That's a lot... You'll need someone to hold the prybar in the flexplate while you see what 200 ft-lbs feels like... :D

On edit: If you do replace the damper, you might as well replace the front seal. You can make a seal driver out of a piece of appropriately sized PVC pipe.

Jim

[MarkMorissette]

Sounds straightforward enough.

Do you happen to know the size of the dampener mounting bolt off hand? One less thing to guess about.

I've read a few threads about people heating up the new dampener in the oven to make installation easier - worthwhile, or not?

[More Power]

An oven + rubber... Might work... I've installed a half dozen of them cold.

Bolt size? It's about yea big.... Just kidding... I don't know off hand. :(

Jim

[MarkMorissette]

Hmm.. Ok, I'll just installed cold then as well - no need to burn my hands any further after last weekends BBQ incident anyways. :p

I'll guess I'll have to go out and get a nut to make an installer out of once I have the old balancer off and can then match the threads, etc.

I wasn't exactly clear on your directions for the installer, but I'll assume that using a long bolt with another nut/washer on it (holding the bolt in place and then running the loose nut w/washer down to press-on the balancer) is along the lines of what you had in mind, correct?

We do have the correct puller, but not a specific balancer installer. Thanks for the tip on not screwing up the crank by trying to press on with the stock bolt, though.

[More Power]

Here's a pic of Dr. Lee's damper installer. :)

http://www.thedieselpageforums.com/photopost/data/500/damperinstallersm.jpg

Screw the bolt into the crank as far as it'll go before beginning the damper install....

Jim

[gmenor]

I just replaced my harmonic balancer for the fluid damper. I had repalced the crank pulley maybe year and a half ago with a after market one. The after market crank pulley was cracked and was stamp "Made in Korea". I love my Burb and will only use OEM or "proven" after market replacement parts. Had the same issue with the vacumn pump from Advance Auto or Auto Zone. Just my two cents.

[MarkMorissette]

Well, for the record..the job is done - it went super smooth. There's something to be said for big trucks with lots of room to work.

I replaced the balancer and the pulley...curiously, the pulley was more expensive then the balancer which is the opposite of what I expected..but anyways.

Glad I did stop driving it - the noise I was hearing turned out to be the pully being fully busted - it was spinning on the plate and the studs were actually whacking into the spokes of the pulley.

All done, here's hoping to a long future for this engine. :)

[Scooby]

Mark- where did you get your balancer and pulley ?? I need them too!! How much were they ??

[MarkMorissette]

Mark- where did you get your balancer and pulley ?? I need them too!! How much were they ??

I picked the pulley up at a local auto parts store (independent little place) and the balancer at the local GM dealership. I get my parts wholesale, but they were still significantly higher then what I saw on some US sites.

The pulley was $104 wholesale at the auto parts place ($300 at GM - wholesale! WTF?) and the balancer was $160 at the GM parts desk.

I was going to get an after market balancer but after reading up a little more here about the quality of such I wasn't too upset when the parts place called and said that they didn't end up getting it on their truck - I paid the $40 more for the genuine AC Delco one instead directly from GM.