So the story goes:

Ever since it started getting really really cold out here in Colorado, the last couple months, my 85 4Runner developed some belt chirping/squealing. Once the motor warmed up it would settle. It was gradually getting worse, and I tried to drive it as little as possible until I could find the time to diagnose and fix it.

First I thought that one of my accessories was locking up, power steering or something, since it seemed to get worse as I turned the wheel. However, after looking at it further, I noticed that the inner pulley on the crankshaft was wobbling a little bit. Not much, just a very slight wobble. Wasn't even both of the pulleys, just one. The inner belt was rubbing the edge of the pulley (as far as I could tell) and that's where the noise came from, also apparent from the fraying on the belt (frayed only on the edge).

So today I go to start it up, since it's been sitting for a week or so. It squealed a bunch, like normal, then suddenly stopped. Then the battery charge light came on and the motor stuttered a bit. I turned it off, pop the hood, now the inner v-belt that runs the Alternator is mangled around two pulleys. It's not snapped, just jumped off the pulleys and got mangled.

So it's an easy enough fix to replace the belt, but what I am suspecting is that it jumped off the pulleys from that slight wobble. (Keep in mind I did check to make sure the belts were properly tight many times during the squealing bit)

Does the wobble mean I have a bad crankshaft? Just a bad bearing on the crank? Maybe just a bad pulley?

Any way I can fix this without having to tear down the entire bottom half of the motor? Anybody have experience with this?

(I did search a bunch, but didn't come to a definite conclusion about the crank.)

Thanks in advance!

 

sometimes the crank pulley retaining bolt works loose, which is not a good thing. at this point, remove the belts, get that 19mm on a breaker bar and remove the crank pulley bolt, then the pulley, and examine. Its possible it has wobbled and screwed up the end of the crankshaft, but hopefully its not gone that far. IF its not loose, but the pulley just has a lot of runout, replace it. Worst case, something caused the crank to develop runout, but that is unlikely.

 

Something is not right, since the two inner most pulleys on the crack are typically made out of one piece of cast iron:



So unless the two pulleys broke/separated, they should move together.

 

Hmm, I will have to pull that pulley off I guess. I only had time to make a quick glance. Thanks for the quick responses.