Doh!, the noise wasnt the water pump or cam belt idler beari

dnsey · Post by **dnsey** » 25 Jul 2006, 16:36

Anders-
I was suggesting that the problem could be related to, but not due to, the belt - I realise that it has been changed. It just seems that the noise points to the cam-drive system somehow.

Mosser · Post by **Mosser** » 08 Dec 2006, 14:30

Just to update everyone,

I havent been able to get to the bottom of the noise with my car, i'm pretty sure the noise isnt cambelt or tensioner or water pump or camshaft related as the noise is most certainly comming from inside the sump at the cambelt end

I havent taken off the sump yet as i havent had time but i suspect it is to do with the oil pump now

alan s · Post by **alan s** » 08 Dec 2006, 19:07

OK, I'll chime in on this one for a minute based on a couple of things that I've come across lately.

If you saw my post a few weeks back regarding a cambelt I fitted to a Xsara VTS. I was supplied with a 116 belt but subsequently discovered I needed a 117 tooth one......the belt I removed was a 116 tooth belt which had been fitted I don't know when by a specialist which was why another 116 was ordered (but that's another story.)
When tested, this belt not just whined, but spasmodically let out with a screech that I isolated using a stthoscope, to the seal or top bearing of the intake cam. It sounded just as though the seal was bone dry and binding and therefore squealing on the journal of the intake cam.
The reason I had decided to change the belt was that it whined when first started and the top end of the engine was clattery again when cold. Once up to temperature both noises quietened to a degree; enough to live with anyway. The giveaway in my case was the taughtness of the belt between the two camshafts. Just a thought which you might consider before totally writing off the cambelt.
To test if the crankpulley is about to fail; get some Tippex (correction ink/paint) and draw a line across the face of the crank pulley so that it appears to be either constant or reasonably straight across the face. Drive the car as normal for a day and check to see if the line is still constant. If it's gine from -- to say -_ that proves the pulley's on the way out.
Hope that's a bit of help.

Alan S

Mosser · Post by **Mosser** » 08 Dec 2006, 21:32

Interesting!, I will check my manual and then go count the number of teeth on my current and old cambelt,

The noise does sound exactly like you described, like a dry bearing, but i have run round my engine with a stethoscope and the noise is comming from inside the sump at the cambelt end, there is a bit of rumble that can be detected when listening with the stethoscope,

There is a 40,000 mile service history gap where i suspect the car wasnt serviced at all, so it could simply be that my engine is now knackered

jeremy · Post by **jeremy** » 09 Dec 2006, 07:35

You can download the Quinton Hazell timing belts catalogue from here in PDF form. It has details of the various belts used on the cars.

http://www2.qha.com/catalogues.asp

citronut · Post by **citronut** » 09 Dec 2006, 08:42

mosser mind you dont become paranoid
regards malcolm

Mandrake · Post by **Mandrake** » 13 Dec 2006, 05:21

Ok,

Time to add my 2c!

I recently changed the timing belt on my Xantia (which is also an XU10J2 engine - 2.0i 8 valve petrol) and a few days after doing it it started making an awful warbly squealy dry bearing kind of noise between 1000 and 2000 rpm, but peaking at a critical speed of 1500rpm. (just like your noise)

I too tried to track down the noise, I knew it must have been something I disturbed when doing the belt but couldn't localize the sound. It sounded a lot like stuffed alternator bearings, but that wasn't it.

The noise was worst when the engine was hot, and it was clearly audible both inside the car with the windows up and to people standing nearby.

I was about to record a sample of the noise and post it here to see if anyone recognised it....

Meanwhile, today we finally got around to doing the timing belt on Dad's Xantia (same engine type) and after fitting the new belt but before refitting the auxillary belt and the covers we gave the engine a quick run.

Shock horror! The same awful noise as my car at 1500rpm!

Not as bad, but clearly the same noise.

Because the auxillary belt was still off that immediately eliminated the alternator, hp pump, aircon, and idler wheels related to that belt, so it had to be the timing belt...

Although we hadn't replaced the water pump on Dad's car, we did replace it on mine, where the noise was worst, so that eliminated the water pump as the noise.

So what was it ? Too much timing belt tension!! Without a gauge there is probably a tendency to have the belt tighter "just to be safe" and with the leverage you can exert on the tensioner with even a small ratchet bar, its very easy to over-tighten the belt.

I reduced the tension to a more reasonable amount (again, purely by feel and estimation as I don't have a gauge) and ran it again - noise gone!

After we put his car back together I whipped the top timing belt cover off mine, checked the tension, and it was even tighter than his had been while making a noise, (infact ludicrously tight in hindsight) dropped it back to a similar lower tension - noise gone!

I still don't know exactly where the noise originates, but I'm betting that its the camshaft sprocket support bearing on the top of the head getting too much sideways thrust on it from an overtight belt.

Because both cars did the same thing I don't think its a case of failed bearings, as both of them didn't have this noise before changing the belts...(and don't again now)

Another thing to beware of is that I discovered that the belt tension increases dramatically from a cold engine to a hot one - a kind of "duh!" realisation in hindsight, but I was quite startled at just how much tighter it is on a hot engine - if you're doing the belt tension by feel instead of gauge you should really be re-checking it when the engine is hot.

So check your belt isn't too tight!! If it was making the noise before you started playing with the belt that could just mean the person before you overtightened it, and you've been dilligently duplicating the overtight tension....

Regards,
Simon

PS Alan - although I didn't count the teeth, this new belt was also very tight getting it on over the tensioner wheel, so I wonder if it is one tooth less as well ?

alan s · Post by **alan s** » 13 Dec 2006, 05:36

Simon,

I know that between the Xantia and the BX there is ONE tooth difference, but offhand I can't tell you which way it goes but from memory, one is a 112 teeth the other 113, so basically a similar set of circumstances.

Alan S

Mosser · Post by **Mosser** » 13 Dec 2006, 09:18

Thanks for sharing that Mandrake,

I have now checked the cambelt and it does have the right number of teeth, so i think i have ruled that out,

But, now you mention it, it does sound like an overtight cambelt, I do usually err of the too tight side when tightening cambelts, and i do now think you have pinpointed the problem on my car, but i think the shell will be knackered now, I will loosen the tension on he belt a little, and if that doesnt cure it, i will take the sump off and look for a worn out shell bearing

Thanks !

alan s · Post by **alan s** » 13 Dec 2006, 10:21

Grab a hard copy of this and keep it under your pillow.

http://62.110.184.188/dayco/pdf/timingBelts-en.pdf

Good info for anyone with a car with a cambelt IMO.

Alan S

Mosser · Post by **Mosser** » 13 Dec 2006, 14:01

Cool !, I will print it out and stick it on the wall in my garage, it will hopefully remind me not to tighten cambelts too much !!

I wont have a chance to check the synergie cambelt tightness until the weekend, so will let you know how it went after then

cheers

Mandrake · Post by **Mandrake** » 13 Dec 2006, 19:17

Mosser wrote:But, now you mention it, it does sound like an overtight cambelt, I do usually err of the too tight side when tightening cambelts, and i do now think you have pinpointed the problem on my car, but i think the shell will be knackered now, I will loosen the tension on he belt a little, and if that doesnt cure it, i will take the sump off and look for a worn out shell bearing

What makes you think its the crankshaft bearing ? Thats a much larger bearing than the camshaft one, and don't forget it has the load of the auxillary belt on it as well. (Albeit pulling in a nearly opposite direction)

Seems unlikely that the cambelt would have much effect on that bearing.... but on the camshaft bearing, thats another story...

By the way mine has been overtight for about 2-3 months making this noise and a quick change of tension has still killed 90% of the noise. (There is still a faint noise at 1500rpm if you listen carefully - but without the warble - but that could just be because the tension still isn't quite right)

Regards,
Simon

Mike Pratt · Post by **Mike Pratt** » 15 Dec 2006, 14:51

Just to let you guy's know, I had a similar issue;low frequency noise at 1500rpm. The issue was with the crankshaft pulley (all hdi's have a two part pulley), it had gone off center (not slipping) which caused the aux belt tensioner to vibrate ( at much less frequency that the engine rpm). When I examined the pulley I could see no visual sign of wear or damage. One good way to see if this has happened is to look under the engine and see if the aux belt is flaping around between the air con pump and the crankshaft pulley. The belt should run smoothly, so if it moves at all in this area you should suspect the crank pulley.