wicked engine shaking at idle 1.9TD Xantia 1998

[falling-out-with-my-car]

Hi,

I have a curious thing causing vibration when my engine is idling. (car details in title)
I suspect the air con compressor but dont know much about them .
when idling air con off the engine growls intermitantly every few seconds like it is being held back.
when I turn on the air con the air-con seems to work ok , The growling is much worse at idle air con on.
if I then open the throttle the growling goes away at higher engine speeds.

Is my compressor on its way out? does this make the car dangerous to drive am I risking beraring failure on a catastrophic level?
Do I need to get the 2cv out for a few days unitl I can get it fixed?

The engine is responsive and smooth/quiet running at anything above 1000 rpm.


thanks in advance

regards Nigel.

[Stewart(oily)]

Sounds like your idle might be a bit slow, your car has the bloody awful aux belt tensioner setup which can also make a racket when the belt is too tight/slack/fitted if you look at the aux belt with the motor idling I would bet you see the belt flapping and the spring loaded tensioner dancing a jig.

[falling-out-with-my-car]

aha Ive actually got a tensioner as a spare it was removed after searching for a weird rattle a few years ago which turned out to be the tensioner spring that holds the pulley in place, but diagnosis with a stick held to my ear doesnt reaveal the same or similar symptoms this time.
The bottom of the serpentine belt is flapping like crazy at idle maybe it has streched in the hot weather slightly.
the belts and pulleys along with the water pump are always replaced at regular service intervals or when the cambelt is due this is due again in about 20K I only do about 8K a year these days in the Xantia. she is ticking over at 950 to 975rpm normal idling speed really.

Have just been out with my testing stick again and the noise is very much like worn bearing noise but it is loudest listenning to the alternator, the back of the spring tensioner or the back of the compressor the noise definately stops when you open the throttle, looks like it will need some ramp time to diagnose which bearing is faulty, Ive never changed the alternator, The trouble is that ther belts take the noise to other componants close by. The spring tensioner as you suggested is not jumping about like crazy just running very steadily. actually about two weeks after the aux-belt was fitted it was retensioned by pleiades who fitted it when we were searching for a similar vibration fault.

[Stewart(oily)]

I wonder if its that needle lift injector playing up ? try disconnecting it and see if the engine sounds any different, I think it should.

[falling-out-with-my-car]

unplugging the needle lift sensor retards the engine timming thats why it sounds different it also over heats & blows sparks out of your exhaust pipe and sounds like the engine is only firing on two cylinders, trust me I know I had a stuck lift sensor once. which was cured by cleanning the connector plug in the wiring loom and no longer feeding the engine veg oil., I pumped put all of the veg and re-filled her with diesel and the lift sensor released it'self, this is definately bearing related but it is difficult to know which bearing it is even with a stick held to your ear and touching componants with the other end.
uncontrolled overheating would have been fairly common lately if it was the lift sensor playing up. the engine management light also lights up when this occurs and I havent had any of this happenning at all.

I thought maybe it was a noisey valve so I drained the oil and replaced it adding some slick 50 as well the engine sounds a lot better
but something auxillary wise is making a racket.

[citronut]

i did the AC pulley bypass with a shorter belt on my TD a couple of years ago Nigel,

as my AC pump pulley bearing sounded like they were just about to break up

[falling-out-with-my-car]

Hello Malcolm!
strange though it sounds it only makes a noise when idling, i am once again beginning to suspect that it might be the tensioner spring again behind the fuel pump, the end of this tensioner that connects to the tensioner pulley has a metal bush for a bearing in the end of the spring and any wear on this bush causes a similar growling sound from the engine whilst idling.

I ran the air-con again last night whilst driving up the A14 and it sounded fairly quiet so now I am having doubts about the air-con compressor bearings going, throttle open, just above idle and bonnet open it is hard to find any bearing noises at all, even with my stick held to my ear.
It is 3 years since this spring was replaced which did silence the growling at idle before, weird that no-one else seems to have had the same or similar symptoms, this all started when the citroen stealers had the car to fit a new set of pulleys & an auxillary belt I think they put something on the car that is the wrong componant for the car. they did say something about using componants from a C5 as they found it difficult to source parts, which sounded weird to me as I have never had any problems sourcing pulleys or tensioners.
regards Nigel.

[Old-Guy]

If this version of the 1.9 (XUD9) has the same horrible tensioner arrangement as the 2.1 (XUD11), eccentric tensioner plus a spring loaded tensioner: as the belt is flapping about at idle, that seems to be the most likely cause. It sounds as though at idle, there's a harmonic vibration in the long length of belt. Has the belt stretched or worn so that it's no longer tensioned properly?

Although it's a PITA to do (on the 2.1 anyway), I'd start by re-tensioning the aux belt and while the spring tension is off, I'd spin both the eccentric tensioner and spring tensioner rollers to see what the bearings feel like.

[falling-out-with-my-car]

Aha,

At last somebody understands my language

I have posted some photo's of the componant that wore out 3 years ago.
This time the noise is significantly worse than the last.
It is absolutley spot on (old-Guy) that the engine seems to have its own resinance frequency at Idle
Which goes away when you open the throttle even very slightly.
regards Nigel.

above is the pulley that was removed after only a very short service period 3 years ago trying to find the illusive engine rattling noise it wasnt this pulley.


This picture shows the Tension spring that bolts to the back of the pulley (above) the bush shown on the left sits inside the larger hole end of the spring (left hand end). This bush wears out and the engine starts to make a growling noise at idle, the vibration is akin to a bearing failure noise without the squeeking.
we replaced this and the growling noise stopped . This time the noise is a lot worse than it was 3 years ago so the metal bush must be severely worn or deformed this time, I dont think there is any decent quality control on these parts any more, the metal bush and its sleeve are clearly not hard enough to cope with the work they have to do.
although changing the pulley the tension spring and the belt stopped the noise it did start to creep back again about a fortnight later and the belt was retensioned, maybe the belts are crap and this causes the wear on the bushes as the tensioner roller moves.? once you have the old tension spring in your hand to inspect the wear on the bush is quite unbeliveably minimal to say the least. its wear limit must be about one thou before the engine starts to resinate making a noise,

I am going to approach this by replacing the belt the pulley and the tension spring just hope GSF do them ?
It might might also be a good idea this time to luibricate the metal bush on the end of the tensioner spring.

[Old-Guy]

The bolt that holds the spring on the back of the pulley hasn't come loose has it? Could its head be vibrating on the front of the block? I'd use a smear of HMP grease on that sleeve.

[falling-out-with-my-car]

Unfortunately it hasnt, I wish it were that simple because this is a real PITA.
I can't sneek up on anybody now.
strange that Citroen and Pleiades have both fitted the bush dry there is no sign of any lubrication in either the sleeve or around the bush when a new one is purchased, it would seem common sense to add some high melting point grease wouldn't it.
Thanks for your patience
Have just done a quick search and found my post from July 2010 when this happened before.
http://www.frenchcarforum.co.uk/forum/v ... p?p=234230" onclick="window.open(this.href);return false;

regards Nigel

[Stewart(oily)]

The tensioner does not pivot on the bolt, if you push the centre sleeve out you will see two needle roller bearings, at least on my spare tensioner there are.

[citronut]

i have seen were the belt is over tight the auto tensioner clatters against the cam belt cover,

only at certain rev's,

when this is happening the long bottom stretch/run of belt flaps away merrily,

arnt the bush sleeves in the tensioner spring sitting in rubber, if so i wouldn't put any grease on them, as this would rot the rubber

[falling-out-with-my-car]

Stewart,

yes I agree the tensioner has roller bearings inside its main piviot in the middle, it has an offset bolt connecting it to a shock asorber (for want of a better word) that sits behind the pulley and is bolted to the engine crakcase behind the pulley, this spring or shock absorber provides the tension for the Auxillary belt.

I have been quite naughty and the last spring I purchased was £25 on flea-bay this time I am going to pay a bit more and buy one from GSF apparently they call it a Auxillary drive belt Vibration Damper and not a tension spring or shock absorber.

So I am going to start there by replacing the Vibration damper obviously it is not damping the vibration from the belt at idle
probably because the metal bush at its bottom end is worn out. it might also be a good idea to replace the auxillary belt at the same time.

Malcolm,

Yes I understand what you are saying about the metal bush in the end of the Vibration Damper its sleeve does sit inside a rubber mounting it is a metal to metal joint between the bush and its rubber mounted sleeve it seems crazy that there is no lubrication between the metal surfaces which are heated to quite a high temperature during use.
Is there a lubricant that doesnt affect rubber I could use instead of HMP Grease? Maybe some PTFE plumbers lubricant to ease friction on the metal bush?

Edit:

Malcolm,

Ive just done a search and apparently I need silicone grease it withstands high temps but doesnt attack rubber componants.
Apparently Servicesol make it and they sell it at Maplins either as a spray or in a 50gram tube it resists temperatures of up to 200 degrees C. I have been doing some reading up on silicone grease and apparently it is a good trouble shooter for electrical problems in older vechicles it stops electrical corrossion and resists water or moisture ingress.
It may be a bit of a gamble applying it to engine componant mounting bolt areas though.
maybe it might be better to fit the bearing bush dry then add some silicone grease spray afterwards?

regards Nigel.

[Stewart(oily)]

I am more than familiar with that bloody tensioner when I replaced the little "shock absorber" on my car the inner steel part and the rubber were both worn through, it was half way through the bolt and the eye on the end was decidedly elongated, only one end seems to wear though, I could be tempted to fabricate my own bush for the worn end and put the thing back in the other way round, Renault 1.9TDs use a similar arrangement and wear them out in the opposite direction, I have one of those on the shelf.