Xantia V6 jerking at constant speed - any ideas ?

[Dave V6]

Hello,

my lovely Xantia V6 with 189k on the clock seems to have a problem. In the last month or so I have noticed when driving at a constant speed, especially at lower speeds where the RPM is around 1200-1500 (e.g. 20-25 mph), that the car seems to be shuddering, or jerking a bit. It feels like the car is being tugged backwards - it is not smooth at all!

I have also noticed it on the motorway, e.g. at around 55-60mph; what should be a nice smooth constant speed drive is not possible as the car is exhibiting this 'tugging' or 'jerking' behaviour.

The problem does seem to be a bit worse when the car has been driven for a while, but I have not kept a proper 'log' of the issue.

I would be very grateful for any advice about what might be causing the problem, and what it might take to remedy...

I know the car is not worth much at its present age and mileage, but it is great to drive when its working properly, so I'd be prepared to put a bit of money into it, but not loads more than the car is worth. I love the car, but I'm not stupid.

Many Thanks!

Dave.

[Stempy]

Just a stab in the dark but maybe lambda sensor? What you really need is a Lexia session.

[xantia_v6]

Can you watch the tachometer carefully and see if the revs go up or down when the car hesitates?

Mine felt a bit like you describe on the day the transmission failed. It was bad enough that I was taking a drive around the block specifically to check the transmission operation when the pump bearing seized.

In my case the root cause was a seized output bearing in the differential, with some metallic shards traveling backwards through the oil galleries (probably when the car was stopped) and lodging in the pump bearing.

Whether the hesitation was caused by the drag of the seized output bearing, or whether both were caused by a blocked oil filter and low oil pressure is unknown.

I hope you are more lucky.

[addo]

Dropped spark, I'd bet. The jerking is unquestionably a reaction torque against the motor mounts, but I strongly suspect it loses a spark briefly, then regains it.

Lexia will show you all the dwell times.

[rabenson]

Sounds like a failing coil pack to me

[Dave V6]

Hello and thanks for the replies. Of course this leads to more questions as I try to sort out the car.

I'm not hugely up on lots of this engine stuff - what is a 'dwell time'?

Is there an easy way to check for a dropped spark? I had the plugs done 2 years ago - about 22k miles or so - is it time for new plugs?

Are there any other symptoms of a failing coil - and is this something that the lexia would show?

Lastly - is there anyone around or near Oxford with a lexia that can help with a diagnosis? happy to pay for it....(but not main dealer prices! Yikes!)

Thanks!

Dave.

[lexi]

First easy call is the coil pack or HT leads. Massive heat and miles plus time take the toll.

However the 4HP20 is getting to about the time?

[CitroJim]

V6 coil packs normally go big-time. Usually they're OK when cold and fail hot, usually cutting two cylinders and lighting the engine management light..

Under these circumstances it doesn't jerk but appears to loose around 75% of its power and effectively becomes undrivable...

There are a myriad of possibilities from engine sensors to the gearbox, even binding brakes.

I'd be minded to get a Lexia session on it and check the engine and gearbox ECUs for stored faults and to confirm correct operation of the various sensors.

It may be air leaks on the inlet manifold upsetting things... MK1 V6s have a blanked off-spigot on the rear of the inlet manifold covered by a rubber cap. That perishes after a while and admits air... Also, if the main manifold gasket was not replaced last time the plugs were checked it's a good bet it'll be leaking.

Check for binding brakes. V6 power can mask this on acceleration but on steady cruise it can become apparent.

One potential gearbox issue may be a slipping torque converter lock-up clutch.

Without driving it, it's hard to be absolutely certain from a distance just what it is...

Indeed, 198K from one gearbox is something of a miracle. It's got to be tired by now.

One test might be to make it 'hold' 2nd and third gears and see if the same happens in those gears, thus possibly indicating a problem on top gear. Do the same in snow mode and see if it occurs.

Reason I say this is that I've known of a case where the B clutch was slipping and it made the 'box feel like it was hunting between third and fourth gears- that would give the tugging effect...

Dave, if you are local to me, I'd be happy to give a test drive and opinion only...

[Mandrake]

Bump!

Did you ever resolve this Dave ? Your symptoms sound exactly like mine as discussed later in this thread:

http://www.frenchcarforum.co.uk/forum/v ... 3&start=15" onclick="window.open(this.href);return false;

Funnily enough a google search lead me back to the forum...(is there anything this forum doesn't know ? )

I've just done a Lexia session and it looks like the dwell times (?) on cylinders 1 and 5 are kaput compared to the other two pairs of cylinders. The jerking/shuddering does indeed feel like the engine shuddering on the engine mounts as suggested by addo. A slight shudder during take-off on heavy acceleration has been noticeable since I got the car (which I originally put down to worn lower arm bushes) but as it has got worse the engine has started to shudder obviously under steady load from 1000-1500rpm, as well as feeling quite down on power.

Anyway, curious to know whether you sorted yours out and whether it was misfiring or whether it was the gearbox on the way out...

[Dave V6]

Hello All,

unfortunately it seems to have been the gearbox on the way out. She got to 203k miles though - 200k was always my plan for her, and I'm happy she got there!

The problem did get progressively worse about 4 weeks ago - to the point where it was shuderring at motorway speeds, and about two weeks ago she finally lost drive while moving through my village. I got both winter and sports lights flashing at the time, and no forward power. This was preceeded immediately by a high pitched whine or whirring which was present from a few moments after I fired up the engine. The whining/whirring was present even when in 'park' or 'neutral' so perhaps something directly connected to the engine crankshaft or flywheel? Stopping the engine, and restarting got me another half mile, and I went to get her a couple of days later and upon starting (with the whining noise) I managed to drive it about another half mile to park it outside my workshop. The whining noise is not good though...

I had a citroen specialist on the phone who thought it was an internal gearbox clutch belt or mechanism that has failed, but a rebuild is out of the question due to cost; So is a gearbox or Gbox and engine swap - just too much money, and I can't do this myself...so the car is for sale as is. MOT has just run out, Taxed until the end of November, and probably won't drive very far on it's own...

Local scrap delaer will give me £175 for it, with an old battery (just to drive it through the gates), so I'm hoping that someone (here maybe) might be interested in it for spares or repairs for £200 (or £275 with the good battery).

If no interest by the 30th Nov, I'll drive her (probably limping all the way) to the local scrappie on the last day of tax.

What to replace her with though...that's the question! I'd love a new model high performance C5! But I'm also looking at a volvo V70-R or maybe an Audi S6... Something big and fast as I do a lot of work that is 2-4 hours from home, and don't want to take too long getting home.

Dave.

[andmcit]

Shame about the gearbox - IIRC, this is the sound of the transmission fluid pump bearing about the pack in -
something Jim mentioned a while ago. It's a shame to hear of a v6 going in a yard to weigh in as there's plenty
if v6 specific spares on it. Is it possible to have more description on the car to help determine how best to move
forwards if just for spares if not repairs?

[CitroJim]

Sorry to hear this Dave

If it's any consolation it did bloody well to get to 203K on one 'box and it must have been well maintained to do that...

Yours has displayed the classic symptoms of failure...

I hope it can be saved. All the guff required to rebuild the 'box is well known and published and anyone who can lift out the engine/transmission and strip the gearbox could get themselves a good car and really it's not a difficult job... If the rest of the car is good then it'll not be money badly spent...

Depending on what's died I estimate a sum total of £500 could see it all good again. It's the labour charges that will be the killer...

See what interest there is before scrapping it please...

[Mandrake]

Also really sorry to hear this Dave

I think I'm in the same boat as you, or will be very soon as my gearbox is giving the same symptoms that you reported a year ago.

It only started doing it in September, (seemingly fine before that) I haven't done a high mileage since then (under 1000 miles) and the symptoms have been getting progressively worse since. It started as a small intermittent groan when applying wide throttle at approximately 1500rpm, which has gradually progressed into a sometimes severe shudder under load at the same rpm.

Other symptoms are that the torque converter lockup seems to intermittently slip when it shouldn't or grip when it shouldn't causing unexpected variations in engine rpm when cruising similar to what you described. Sometimes you will accelerate at 60mph and the revs will rise quickly due to torque converter slip then they will drop again a moment later as the clutch locks, which it wasn't doing a few months ago.

If I had to guess, and based on discussions in my thread I would say that the torque converter clutch is breaking down, with the groaning noise and shuddering being the lockup clutch itself shuddering...if it progresses much further it may start to dump metal particles into the oil stream that will block the filter (causing clutch slip due to low pressure) or damage other bearings, at which point it will be game over...

I still haven't determined whether it might still be salvageable with a few rapid oil changes (I've done one but need to get another one done) or whether its too far gone.

As Jim says you've done very well to get 203k out of it, especially if the symptoms first appeared at 189k, my box has only done 101k and the symptoms began less than 1000 miles ago!

Can I ask what mileage the car had done when you first got it, and whether you had done any gearbox oil changes between the time you got it and the time the symptoms began ? Also once the symptoms started at 189k, did you try doing any gearbox oil changes to see if it resolved the symptoms ? How did the symptoms progress over that last 14k ?

I'm hoping that a bit more information in the post mortem of your gearbox may give me some hints as to how serious the condition of mine is, how quickly its likely to progress, and whether its terminal or whether disaster can yet be averted...

[Dave V6]

Hi again to everyone,

yes, I was hoping not to bring it to a scrappie... although the local place does parts recycling - they were very interested in the alloy wheels!

If anyone's interested:

The car has been mine since 120k. I have had it serviced just under each 12k, as directed by the onboard service indicator (every 12500), with gearbox oil changes (with the proper stuff, always by local citroen/french/euro specialists) every 2nd service from 140-180 (approx) then every 12000 miles. I've done my best to look after it, but my things is electonics and acoustics, not enginey things. I just enjoy the driving.

It's still on the original exhaust back box (and cat I think...but I think the mid section may have been replaced, but can't remember for sure).

It has had a reconditioned offside drive shaft and a new lower engine mount/driveshaft bearing holder just this summer, and has had new cambelts at around 160k or so (might have been 150k? was a couple of years ago). New plugs went in while the cambelts were beign done.

A recon starter motor was put in last winter, and a recodnitioned hydraulic pump went in the year before.

It probably needs some spheres as they have not been done in 3 years and the ride is getting hard, and I think a couple of the electric windows don't work (likely to be wiring in the door looms). At last year's MOT I was advised that the drop links might need doing for this year's, but the gearbox failed 2 days before my test!

The locks work fine with central locking, but the door sliders for the locks are not great (left hand side ones are not working and sit in the holders without moving). The interior is black leather and is in good condition. All headrests are present. Electric tilt and slide sunroof.

The body panels and doors/hatch are in really good condition (nearside front door has a dimple dent in it), although the silver paint is a bit scratched here and there. The bumpers are silver, and have the usual scratches for 200k miles... (front bumper has has a few bumps, but nothing serious. It's a well used but well loved car...

Apart from a couple of windows, the electrics all work fine, but cruise control has never worked since I've had it...

I have loved this car, but when Xantia V6's with nearly half the mileage are being sold for £3-400, it does not make sense for me to put more than that to repair a gearbox...

Of course - if anyone's got a working gearbox to sell me, then she might be back on the road. Otherwise, I'd like to see it go to good use, rather than actually scrap metal...

Thanks to all for the advice when I've needed it. If anyones got a Xantia V6 for sale I'd deinitely be interested in it, because as I said in a previous post I do a lot of driving for work and don't particularly want to hang about getting home after each job. So it's either another of the same, or else a fast estate of some sort...

Cheers,

Dave in Oxford.