[Crashly]

Yesterday It happened!!! The car was towed home by Triple A. It turns out that the Harmonic balancer fell apart!!! My wife was driving it and then it started making some weird noises. So she had it towed home. Good thing she did. When I inspected it the outer balancing ring was completly seperated from the inner ring and it was bouncing around.
So here is the replacement I thought that a few of you guys may be able to use this info in the future.
1st step; remove the upper radiator shroud. 10mm Bolts, Hint: Use a long extension 12-16" it makes the job quicker on the lower bolts.
2nd step: Remove the fan blade 4 nuts 13mm open end wrench. Hint; Leave the serpintene belt on and it will hold the fan for you, then just loosen the belt tensioner and turn the fan 160 degrees to reach the lower two nuts)
3rd step: Remove the serpintene belt, 1/2" drive, turned toward the passenger fender will loosen the tensioner and therby releases the belt
4th step: Remove lower crankshaft pulley, and harmonic balancer bolt: using 15mm socket, and 15/16 socket: Note since I had removed the serpentine belt the pulley wanted to rotate, A easy way to fix this is on the backside of the pulley there is plenty of space for a large cresent wrench to hold onto 1 of 4 large metal metal forgings in the pulley assembly. I used a air impact wrench on the 15/16 socket that holds the harmonic balancer to the crank. You can also use a braker bar on the 15/16 socket, and disconnecting the fuel run solenoid turn the car over with the starter and that should loosen the belt (This way is kind of dangerous and can damage things like the radiator... be careful)
5th: using harmonic balancer puller, steering wheel puller, use two of the 15 mm bolts that hold the pulley on attach the puller and remove the harmonic balancer
6th: I would highly recomend replacing the Front crankshaft seal at this time. I removed mine by bending the seal down towards the crank with a hammer and screw driver then prying it out. Instalation is fairly simple just make sure that the O/D is fully greased with assembly lube and the ID is greased as that is what seals against the harmonic balancer.I used a little patience and a flat faced hammer and tapped the new seal back into place.
7th Step: Reinstall the harmonic balancer, Make sure that the woodruf key is still in place.
8th Step reinstall the belt and shroud and enjoy.


This is a fairly easy project and WITH THE RIGHT TOOLS will only take 1.5 hours at a easy pace. The parts around $160. The GM part Number is 10154688. the dealer cost for this replacemt would have been un the 500n dollar range...ouch!!

 

[DieselPro]

Sounds pretty good. I would advise timing chain replacement at the same time. I recommend using the 6.5 mechanical chain set and reusing the lower crank gear as the most economical means of doing it. The 94 up version has the special crank sensor and boosts the price way up.

 

[TedReminder]

I'm looking at replacing the chain on my 94. Pro, on your recomendation, Is that chain available at Napa or Autozone?
Also, I have been having a loss of fire in a cylinder or 2 when coasting, especially with the brake on. It will fire right back up if I rev it past 2500 or so. Otherwise the truck runs great and gets good mpg. If I keep the revs up over 1000 when coasting it will not lose fire.
Can a sloppy chain mess up pump timing enough to cause a loss of fire?
Thanks,
Ted

 

[DieselPro]

All auto parts centers have chains. Ask for a 93 model set. When the chain goes bad it's hard to notice as the engine performance degrades so slowly. I found out about the chain trick from a major engine builder. They only changed the upper half in their rebuilds. The lower sprocket from GM is quite expensive. I've probably done a dozen engines and in each one the chain was tight with the old bottom sprocket. Of course somebody here is going to say that's stupid but I know it works fine. NAPA quality use to be the best and we use them exclusively in our shop but their quality has dropped to the lowest level. Pencil pushers there have gone the way of Walmart. Find the cheapest supplier and use them till it hurts. Warranty from them is almost none existent. You have a unique problem with your truck.

 

[mp4037]

Sounds pretty good. I would advise timing chain replacement at the same time. I recommend using the 6.5 mechanical chain set and reusing the lower crank gear as the most economical means of doing it. The 94 up version has the special crank sensor and boosts the price way up.

What is the crank sensor? I have a 95...can I use the 93 set? Will it set off any codes if it is missing this sensor?

 

[bobbiemartin]

I bought a Cloyes 3 pc timing chain set for a electronic truck at a local parts house for less than $100. Came with the proper reluctor on the crank gear. They had to order it, but had it the next day.
I might suggest a harmonic balancer installer tool to install the balancer. Saves a little wear on the thrust washers.
I have an almost new DSG gear set listed in the for sale section - cheap!

 

[bobbiemartin]

What is the crank sensor? I have a 95...can I use the 93 set? Will it set off any codes if it is missing this sensor?

The crank sensor is on the crank timing chain gear. Your truck won't run without it.

 

[DieselPro]

What is the crank sensor? I have a 95...can I use the 93 set? Will it set off any codes if it is missing this sensor?

Leave your old bottom gear on the crank. The cam sensor reluctor wheel is part of the crank gear.

You will just use the top cam gear sprocket and the chain. Makes install easy and saves you a little money.

 

[mp4037]

Leave your old bottom gear on the crank. The cam sensor reluctor wheel is part of the crank gear.

You will just use the top cam gear sprocket and the chain. Makes install easy and saves you a little money.

I'm not real excited about doing the timing chain set. I just figure i might as well do it as preventative type maintainence if I have to replace the harmonic balancer. I see that DP suggests this, is this a good Idea? Any potential problems?

I have other repairs that I will be doing and I would like to do them together if possible. Like hose replacements, vacuum pump, idler and pitman arms, steering stabilizer, etc.

Is there anyway of checking if the balancer is starting to fail and is the cause of the vibration without actually replacing it?

Also in the above post there is a GM part number...are all the balancers out there made by the same manufacture? Any specific ones prone to failure.

If I do end up replacing this part I sure would like to replace it with the best that I can find. Any suggestions?

I have new tires and new u-joints, rotors studs and pads. The vibration is the same before and after the new stuff. It definitly feels like it is in the motor...I can feel it in the acclerator pedal and and a different rpm's.

Diesel Pro Wrote:Sounds pretty good. I would advise timing chain replacement at the same time. I recommend using the 6.5 mechanical chain set and reusing the lower crank gear as the most economical means of doing it. The 94 up version has the special crank sensor and boosts the price way up.

Is the sensor on the lower crank gear that you recommend leaving in? I just want to make sure that I understand you correctly.

I know this is a lot of questions in one post. Maybe the answers will help others as well

 

[guybb3]

Also in the above post there is a GM part number...are all the balancers out there made by the same manufacture? Any specific ones prone to failure.

If I do end up replacing this part I sure would like to replace it with the best that I can find. Any suggestions?

Fliudampr is supposed to be coming out with one anytime now but all their diesel dampers cost about $400.

 

[mp4037]

Fliudampr is supposed to be coming out with one anytime now but all their diesel dampers cost about $400.

Are all the balancers out there maufactured by the same company for the 6.5?

 

[Stingray454]

Thanks for the advice and step by step instructions. How many miles did you get out of the original balancer? I'm going to be doing the 150k service on my truck soon, and I'm wondering if I should just replace it as a preventative measure?

What about the crankshaft pulley that bolts to the harmonic balancer? Shouldn't that be replaced too? That pulley looks like it has an inner and out ring connected by rubber in the middle. I've seen a few people post about that rubber disintegrating in that pulley and the pulley separating. I thought that was the harmonic balancer originally, but I think it is just the belt pulley in front of the balancer.

 

[Diesel-T]

mp
My truck has a slight vibration between 35 _55 mph. Seems to be
tied to ground speed.Varrying engine speed does not affect it.
Just mention it as it may be one way to help eliminate possible
general soource of vibration.eg engine versus drivetrain tires etc.

 

[mp4037]

mp
My truck has a slight vibration between 35 _55 mph. Seems to be
tied to ground speed.Varrying engine speed does not affect it.
Just mention it as it may be one way to help eliminate possible
general soource of vibration.eg engine versus drivetrain tires etc.

The vibration that i'm referring too started maybe six months ago. It's not getting any worse but i'm concerned because it feels like the motor. I can feel it in the accelerator pedal...sometimes it seems as though it is high frequency and tickles my leg. Someone mentioned an exhaust drone but I haven't been able to trace it to that or anything else.

 

[ChevyDave]

does anyone have a part number for the crank pulley in front of the HB? I've been looking around but nobody seems to have it.