I found out that the previous owner of my blazer put the wrong bolt into the crankshaft pulley. I am talkin about the main bolt in the middle of the three smaller ones. I know I shouldnt be driving it, but I have to get to work somehow. I was wondering if anyone knows where I could find a replacement bolt. I have tried everywhere from junkyards to online places to all the local stores (i.e.-Napa, Advanced etc.) The crankshaft also has had a lot of vibration even before the bolt came out. Will this go away with getting a new bolt or will I have to replace the whole crankshaft. As you can tell, I am not knowledgeable in this area of my blazer at all. Any help would be much appreciated.

 

It really depends on how bad the threads are in the front of the crank.

Have you tried the dealer?

 

Any decent auto parts or dealer parts dept will be able to sell you a harmonic balancer crankshaft bolt for a chevy 4.3 liter... You may need to replace the harmonic balancer as well... not a big deal, you just need to buy or rent a harmonic balancer puller.

 

How'd you find that one out? The crankshaft pulley bolt isn't something you check everytime you pop the hood. lol

 

Well on top of that I have a class 1 leak coming from my radiator so I happened to be in the neighborhood. On top of that and some vibrations I have been feeling while driving. I fired it up and saw that the crankshaft and pulley was vibrating. When I went to tighten the bolt up, it came right out.

I will have to check with another dealer, the one in Fairborn said they couldn't get one for me. I will try another dealership.


bandidolenny- So is it as simple as getting the pulley off, using the harmonic balancer puller and putting the new harmonic balancer back on...sounds simple. Thanks for the info. When I find the part I will give it a shot.

 

When you get the harmonic balancer off, you will see that there is a woodruff key that aligns it on the crankshaft. Perhaps they are misaligned or the harmonic balancer itself is coming apart. Either would cause a noticeable vibration.

 

My money is on the balancer coming apart and causing the vibration, you should drive it as little as possible because this will cause you a whole bunch of expensive problems, ie: at the least take out the main front seal, at worst...take out the main bearings at the front of the crankshaft. A replacement bolt should be a-dime-a-dozen at a wrecker's. As already mentioned you need to chase the threads with a tap because chances are they're a bit screwed up with the wrong bolt in there. When you do install the new bolt don't force it...if it becomes tight before seating and you do, you'll just gaul up the threads and it'll never get tight.
Get a used balancer and bolt from a wreckers and when you put it in, clean up the threads in the crank then use some brake cleaner, rubbing alcohol, etc. , anything that doesn't leave a residue, to clean any oil, grease, tec. from both and then use some locktite on the threads to hold the bolt in place. You can buy one-use little tubes from just about anywhere, just make sure you use the removable type ( blue container) just in case you need to remove it later.