sounds like the rubber damper is worn on the harmonic balancer. if this is the case you will have to replace the harmonic balancer.
either one of your pulleys on the motor is froze up or the harmonic balancer at the bottom of the engine is coming off.I had this happen to me on my 2000 montana.
You didn't state what vehicle you have but with most vehicles all the belt driven accessories are driven by pulleys attached to the harmonic balancer so you will be driving without a functioning alternator, power steering pump and water pump not to mention you will probably be splashing out motor oil profusely. I give it about 20 to 30 minutes before the engine seizes.
20 foot pounds of torque is called out for the water pump pulleys. The drive bolts on the balancer are the same size, count and diameter. If you're worried, use a little loc-tite. Good Stuff
Remove any bolt on pulleys, remove center bolt counterclockwise, remove the harmonic balancer with proper puller available for rent or sale at your local auto parts store.
If your talking the main harmonic balancer on the crankshaft, you will need a puller to remove that. I can't think of any pulleys that would allow you to pull them off by hand. Your local autoparts store will have a removal tool for more than likely around 20-25 dollars.
the drive belt is the belt or belts that runs off the harmonic balancer and drives all the accessories-alternater powersteering water pump aircondition compressor and anything else
It could be the harmonic balancer. This is the first pulley on the engine drive shaft that drives all the other pulleys with the serpentine belt. It is quite easy to look at it and see if the rubber has deteriorated. I had this problem with my '92 PA.
not always usally makes an noise close to a rattle or knocking hence harmonic.use a broom stick or hose to use as a listening device to locate the exact place of your noise could be starter sticking in(ect...)
It is part the process in changing a timing belt. If you look at the instruction for changing a timing belt you can stop once you reach that point. It does not require removing the timing belt though just most of the pulleys, Idler belts and if you want to be safe the radiator. The bolt holding the pulley and harmonic balancer can be tough to get out, and getting an impact wrench in there to pull that bolt is almost imposible without removing the radiator. The engine crank will turn freely as well which compounds the difficulty. http://www.ehow.com/video_4978619_timing-belt-replacement-remove-harmonic.html http://www.justanswer.com/ford/143nf-replace-timing-chain-1989-ford-ranger.html
dirt and dust usually could possibly be a dry worn belt but also check the belt tensioner it can be to weak and allow squeaking Also, sometimes a belt with small cracks in it will make noise. If you haven't replaced the belt for a while I'd be suspicious of the cracks. I've had this happen...check to make sure that water or anti-freeze did not hit the belt. Either the belt is worn out or the tensioner is defective. This also may be caused by your pulleys. For instance if the harmonic balancer gets out of line with the rest of your pulleys it can cause a squeak or if the bearing in one of your other pulleys has gone bad it can cause a squeak also.
This depends on which pully you want to remove. The idler pulleys simply bolt on. The pulleys mounted on the water pump also bolt on. If you want to remove the harmonic balancer pulley, you'll need to remove the bolt in the center of the crankshaft, then use a puller. The pulley on the power steering must also be removed with a special tool. AutoZone(r), Advance Auto(r), and Murray's Auto have these pullers in stock and you may be able to rent one. You need a special puller sometimes rentable at the parts store.