Stan944

What exactly happens, and what sort of noises one should expect?
Thnaks?

Yabo

Usually the bearing in the shaft that spins it wears out and the shaft begins to rock, and usually leak.. Eventually the bearings will seize and snap your timing belt.

Usually you'll get a weeping drip from teh bottom of the waterpump when it's on it's way out. It doesn't always happen that way though. If you haven't replaced it in the last 50k or so.. you might want to do it as preventative maintenance. It's cheaper then buying new valves when your belt snaps

Stan944

Thanks Devon, I replaced mine about 20k ago. I asked because I'm trying to figure out the origin of a strange intermittent noise I get on cold engine (high-pitched 'bzzzt' several times per minute). Could this be the sound the bearing makes when it seizes?

Luis de Prat

The sound of a failing waterpump is hard to miss. At first it sounds like a continuous whine, then it becomes louder, and finally, when disaster is imminent it makes a grinding noise.

If you hear a faint whine coming from the right front of the engine as you sit in the car at idle, it's most likely the waterpump. However, what you describe may be something else. Especially if it's intermittent. Waterpumps make a more continuous noise when they begin to fail.

Stan944

Thanks Luis. Can a failing bearing make such intermittent noise, or bad bearings make continuous noise only?

Yabo

Overtightened balance belt can also make a whine, same for the timing belt but the timing belt being too tight is usually teh waterpump whining. Try a screwdrvier or stethascope against the waterpump pulley (in the middle where it is smooth and wont wrap you up in it if you are careful!) and check if it is loudest from there? I'd take off all accessory belts and be cautious of fans and crank pulley, but it might work.

Luis de Prat

In my experience, the noise is continuous not intermittent. As for the whine coming from the belt, that's possible too, but you didn't mention having just changed your belts, did you?

Stan944

This noise started about a week ago. I put new belts more than 3 months ago, and retensioned them with Krikit 1. The tension should be OK. I'm familiar with the whining of the balance belt, but this is much different noise.
I suspect things got loose on the crankshaft, making the oil pump not spin. If this is it, than it's a very early stage, because I don't see any loss of the oil pressure correlated with this noise.

Stan944

Well, I believe I found the origin of the 'bzzzt' sound: the tensioner roller of the balance belt has a chiped out piece, and I actually have managed to repreduce the sound by spinning it in my hand.
So I tried to run it with the timing belt only, i.e. the balance belt out. No more 'bzzzzt'. Good news.

But there is a new noise! also intermittent, this time it sound as if somebody was tossing a small stone against a wall. What could it be? So I took the timing belt out. The tensioner of the timing belt has very little play. The water pump spins nicely. The idle roller of the timing belt has some play, but not that much. Some internal debries in the water pump?
HELP!

Rock

I dunno ive heard that the waterpump can seize and snap your belt, but the belt just rides along the pump pulley. I dont really see that instantly killing a timing belt

Yabo

Rock, the waterpump is a pivot of the belt, so yes it is just riding on it but all the tension of the belt is on it.. and it's moving pretty damn quick.. When it stops, it is going to heat the belt up an awful lot and itll melt/snap.

Sam I am

"Rock, the waterpump is a pivot of the belt, so yes it is just riding on it but all the tension of the belt is on it.. and it's moving pretty damn quick.. When it stops, it is going to heat the belt up an awful lot and itll melt/snap."

I have had this exact thing happen, although I caught it before it snapped becuase I was watching my temp gauge. The water pump roller had seized and stripped the belt of many teeth and burt rubber shavings coated the inside of the belt covers. I was very forunate.

Rock

Criekey!

Sam I am

Yeah, I almost had a heart attack when I realized what had just happened!

Stan944

I think I didn't make it clear, and got you confused.
Neither of the belts failed, I took them off one by one for testing.
The water pump didn't fail - I asked originally before I checked things (I wanted to educate myself before taking things apart), but the water pump appears normal.
The question I have now is what's the origin of this new noise: it sounds as if somebody was tossing a small stone against a wall, and it comes from mid or lower part of the engine. This is with the timing belt installed only, no other belts.