Harmonic Balancer Problems

[kcel2001]

Hey everybody. I was working on the trailblazer the other day and happened to look down and notice that the harmonic balancer bolt doesn't look to to be spinning true. It spins in an almost oval pattern looking from above. The engine is out of an 03 4.2 trailblazer ls with about 120,000 miles on it. I can take a pry bar and with moderate pressure I can move the balancer about an 1/8th of an inch. There isn't any oil leaking from around the front crank seal so I don't think it's a bent crank snout otherwise it would've blew out the seal and run like crap, but I could be wrong. I'm really thinking its a bent balancer bolt but just wanted to get some opinions on what you guys think before I go any further. I recorded a video of the balancer with the belt off and I'm sorry the quality isn't the best but an iPhone is all I have to use. Here is the link http://youtu.be/nH1yRLZJw5Y . The video does drop down into slow motion. Thank you for your time.

 

[Mooseman]

I had before on my 4.2. The bolt was loose. Check to see if it's still torqued but be warned, it takes a load of torque (110 ft. lbs + another 180 degrees ). If it's still tight, I wouldn't worry about it. When I did my timing chain, I used the bolt from the donor truck as I didn't trust the original one if it came loose like that.

 

[kcel2001]

Well I ended up pulling the balancer bolt to check and see if it was bent. This particular bolt was all threads, no shank. So I put it on a straight edge and could see that the bolt curved up by about 3/32". I ordered a new bolt, GM p/n 11609792. This new bolt had a shank with about 2" of threads. It also looks like it came with red loctite pre-coated. Installed the new bolt and Mooseman is right, it is a crap load of torque. The 110 ft lbs was easy but the other 180 degrees, not so much. My brother kept the crank from turning by holding the flywheel with a pry bar and I used a 24" breaker bar with everything I had to get that 180 degrees. In the end problem solved. Balancer bolt looks to be spinning nice and true now.

 

[Capote]

Mines been doing the same thing now, I got a lot of vibration while sitting in Drive with the brakes engaged [emoji29]

 

[Tiggerr]

Mines been doing the same thing now, I got a lot of vibration while sitting in Drive with the brakes engaged [emoji29]

Could be motor mounts as well

 

[Capote]

Could be motor mounts as well

That's on my to-do list. OEM motor mounts are pricey *sigh* [emoji30]

 

[xavierny25]

Could be motor mounts as well

I'm going to jump on in here because I'm having an issue similar to all this. I was under the voy and noticed my voy ' s harmonic balancer has the rubber peeking out something like someone went at it with a flat screw driver while it was running. I'm also thinking it may be my motor mounts are shoot. I start the truck just fine but once in drive I'm getting the annoying vibration but after about 10-15 minutes of driving it's gone. If it sits off for more than 2 hours it's all it again.

I'm first going to tackle the harmonic balancer cause I know it's definitely no suppose to look like that and it might solve the vibration. If not then I'll replace the motor mounts.

If any one has ordered one or has a part # Please get it to me. Thanks in advanced guys.

 

[Tiggerr]

That's on my to-do list. OEM motor mounts are pricey *sigh* [emoji30]

ACDELCO #12578069

$70 on Amazon with free shipping...not prime though

 

[xavierny25]

So as some of you may already know I changed out my harmonic balancer. Something just didn't look right with it and I had to get it out of there. Sure enough there was something very wrong. I took a 2 foot level across it and I could see the inner metal ring was flush on one side and pushed in on the other. My thought is that the rubber on the inside failed and caused it to shift just so slightly. So while the engine is turning the outer ring where the belt sits would wobble a bit. And this of course will eventually cause a belt to fail and maybe even ware out other pulleys prematurely.

I'll post a picture of the actual level on the harmonic balancer later so it can be seen. The picture on top is the new balancer the one on the bottom shows what I saw that made me want to change it out.

 

[Capote]

Holy crap man, yes I wanna see pictures of that

 

[xavierny25]

Holy crap man, yes I wanna see pictures of that

Be patient I'm still at work. Lol...
As one can also see my idler pulley and tensioner pulley are new replaced those when I did my water pump about 2 yrs ago.

So far no jet engine sounds when I'm out and about early in the morning. The used fan clutch is working out great. And the used one I picked up has 150000 plus miles on it. Smh. I just don't get it.

 

[Capote]

Be patient I'm still at work. Lol...
As one can also see my idler pulley and tensioner pulley are new replaced those when I did my water pump about 2 yrs ago.

So far no jet engine sounds when I'm out and about early in the morning. The used fan clutch is working out great. And the used one I picked up has 150000 plus miles on it. Smh. I just don't get it.

I've also replaced those on mine. My harmonic balancer is visually a tad wobbly on that bolt on the outside, it has me worried.

 

[xavierny25]

I've also replaced those on mine. My harmonic balancer is visually a tad wobbly on that bolt on the outside, it has me worried.

Could you amazing it it really failed and ripped out of the rubber.[emoji27] it would definitely cause some major f - in issues.

 

[Capote]

Hell no, that would be horrible. My phone can't pick up the slight wobbling when I film it unfortunately, so I can't show you

 

[xavierny25]

Hell no, that would be horrible. My phone can't pick up the slight wobbling when I film it unfortunately, so I can't show you

I see you and a few other mention the actual bolt being wobbly. In my case it was the outer ring that holds the belt I saw to be wobbly .

 

[Capote]

I see you and a few other mention the actual bolt being wobbly. In my case it was the outer ring that holds the belt I saw to be wobble.

But why would just the bolt wobble and not the whole ring?

 

[xavierny25]

But why would just the bolt wobble and not the whole ring?

I don't know..... That's your issue not mine. lmao. Jk. I'ma guess the bolt is warped with that extra 180 degree you got to put on it after tork spec. I wouldn't doubt it would do that. Haven't taken I look at mine since I did it but I will later today.

 

[xavierny25]

Left side touches right side has a gap. Wish I had a L square or t square but this shows you what I'm saying.

 

[Daniel417]

Thread hijack. My harmonic balancer is not spinning true. I can see it vibrating at idle. I can also feel vibration in cab. Anyone have a replacement number?

 

[xavierny25]

That's what I ordered for my 08 envoy I6

 

[Daniel417]

Thank you xavierny. I believe I have you similar problem to what you where having. I took my belt off and pryed on the balancer to check for play. And it seems to have straightened it out. Also ran engine with belt off to make sure it wasn't anything else. I'll examine it better this weekend when I pull everything apart for a differential swap.

 

[alupparelli]

I had before on my 4.2. The bolt was loose. Check to see if it's still torqued but be warned, it takes a load of torque (110 ft. lbs + another 180 degrees ). If it's still tight, I wouldn't worry about it. When I did my timing chain, I used the bolt from the donor truck as I didn't trust the original one if it came loose like that.

Hi !!
In my trailblazer timing cover seal is bad and I have to remove the Harmonic Balancer; for this I have to block the crankshaft to remove and reinstall the Harmonic Balancer, my question: How do I lock the crankshaft ? Supposedly to use the EN-46547 tool to block the Trailblazer 4.2L crankshaft, however, I do not get how using this tool, and do not own my disposal impact pneumatic tools and want to know which suggests GM to do this job.
Thank you very much for your answers.
Adrian L.