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Crankshaft bearing noise

C

chopper

PCGB Member
Member
My 2000 996 has started to make a scary noise tonight, I thought initially it was the alternator bearing, but when I got home I put a screw driver on the alternator engine running and all sounded normal, however when I looked around I noticed the crank pulley is moving about, back and forth, and I think the noise is there, any ideas?

I have stopped driving it but would appreciate any advice

Gary
 
If it is the crank pulley I can only think that the pulley itself has failed in some way. Are you sure it isn't the water pump pulley though?
 
Not completely sure, how would I tell? Is there normally movement on the crank pulley

Thanks Richard
 
The crank pulley is dead centre, and the water pump is lower and to the left. The crank pulley is a snug fit on the crankshaft, so if it is wobbling, then it is more likely that the pulley has failed than anything more untoward. Not that I have heard of it happening before.

The water pump, on the other hand, is more known to fail. The bearings can go, which would cause a wobble, but the plastic impeller blades also break up. They usually start leaking badly, which is normally the first sign.

If you are handy with spanners, the best thing to do is remove the drive belt, and spin the pump. You will soon know if the bearings have gone. You will be able to check the crank pulley at the same time.
 
Thanks Richard

I re checked it this morning and you are as always correct, it is the water pump, my initial panic of bearing noise threw common sense! I will order one today and fit at the weekend, after the re fill is it easy to bleed the system?

Gary
 

ORIGINAL: chopper
......, after the re fill is it easy to bleed the system?
Click to expand...

It can be a real pain. My advice is to drain as little as you can, and collect as much as possible of what drains/escapes, so you have an idea of how much needs to go back in. No doubt you will have the back of the car in the air, which will help a little to stop the front section from draining. Vacuum filling devices work best. Ideal if you could beg/borrow one.
 
Update:

Well as Richard correctly identified it was the water pump, very happy about that, removed the pump, quite an easy job, sadly bent the gasket pushing the pump back up to re fit and stupidly hoped it would not leak, but it did, so deep joy I get to do it again next week! The coolant re fill is interesting, but you need to take it slowly and it will bleed and fill.
 
At last all done! she is running beautifully, no noise and i found a great way to bleed the water system if anyone want s to know.
 
As you will have the car jacked up at the rear to facilitate the pump change the water will tend to lay in the front of the car, i.e rads and pipes. When you have completed the job, leave the car on jacks, very very slowly add collant and water, wait each time for it the drain away with gravity, continue this until you cannot get anymore to flow. Secure the cap, open the vent and start the car, run for about 5 minutes and then open the cap, hold about 2000rpm on and slowly add any additional collant. Get her up to operating temp, with the valve open and drive locally for a few miles, each time she is cool add a little water, its a very small amount and continue this each time its cold until you can't add anymore. No stress, no mess and perfect temps.
 
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