Bad crank or bad Harmonic balancer?

veesix · Mar 25th, 2006, 06:39 AM

The crew at the Nissan dealership called me last night, with some strange news.

I noticed, before I brought it in, that the running engine was not turning the drive belt for the alternator, A/C compressor, and the power steering pump. It would start spinning slowly if I gave the belt a push.

The service department says that it's a bad crank or a bad harmonic balancer. Anyone ever hear of this type of problem?

Xeno · Mar 25th, 2006, 06:47 PM

Maybe chuck key broken from crank pully??

veesix · Mar 25th, 2006, 06:57 PM

I am looking through my Haynes manual for a good picture of the balancer and pulley arrangement. So far, I'm in the dark about this part.

Yesterday, I spoke to a kid at the dealership and he had me thinking that a key may have sheared at the crank and damaged it's surface (making a repair impossible).

87pathfinder · Mar 25th, 2006, 07:24 PM

ive got an 87 pathfinder my harmonic balancer/crank pulley went a few months back. it caused the belt to break and over heat. the part was cheap from nissan maybe 180 around there. good luck.

veesix · Mar 26th, 2006, 08:42 AM

The truck does have 201,000 miles, so I'm not surprized that the balancer needs replacing. It seems that there are two ways that the balancer can fail. Is this right?

The crankshaft pulley looks to be attached to the front of the damper (somehow).Anyone know how this can fail?.

Also, the damper bolts into the front of the crank but is it also locked in place, along with the timing pulley, with the same Woodruff key? I have to wonder if half of the key sheared.

Thanks, veesix

50BMG · Mar 26th, 2006, 01:34 PM

Check for a broken crank KEY. mine broke a few years back. the bolt in the front of the crank only stops the balncer from going through the radiator. when the key breaks the crank will spin but the balncer will ether stop or drag on slowly if some of the left over key if still there. you will not know till you take it apart.

50BMG · Mar 26th, 2006, 01:36 PM

By the way the timing pully and the balncer use 2 diffrent keys

veesix · Mar 27th, 2006, 08:56 AM

Thanks 50BMG, good to know. I am wondering if a sheared key can ruin the end of the crank. I doubt it, but if it is true, the engine will need a rebuild.

Any one know how the crank pulley can separate from the balancer?

Xeno · Mar 27th, 2006, 01:08 PM

No they make the key from a softer metal than what it is insert in to. (thats why they use a key)

veesix · Mar 28th, 2006, 12:52 PM

The Dealership gave me a ring late this morning. They say that the key is sheared, and the end of the crank should be redressed (or tapered) to fit the new balancer.