Xantia V6 broken exhaust (update: and rough low rpm running)

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addo
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Post by addo »

I see exactly that with the early Blingos, too! :shock: An R4 fourgonnette.

Northern_Mike

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Northern_Mike »

addo wrote:I see exactly that with the early Blingos, too! :shock: An R4 fourgonnette.
I love ours. It's brilliant. It's great fun to drive and oh so practical. I see it more as a 2CV update though. . a car I loved as a teenager!

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CitroJim
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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by CitroJim »

Northern_Mike wrote:I see it more as a 2CV update though. . a car I loved as a teenager!
Same difference Mike. You had a 2CV as a teenager and I had an R4. Two actually - the first had 6v electrics!!!

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by lexi »

or taking large dogs to training.
I just knew they were popular with the "dogging" brigade :lol:

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Sorry to interrupt the fun guys :lol: but a comment on the gearbox after changing the oil on Sunday.

Today I've noticed a sudden (since yesterday) large difference in the behaviour of the torque converter lock up - previously it felt to me like the engagement of the TC clutch was intermittently slow and wishy-washy, sometimes taking 2-3 seconds to lock up in 2nd/3rd during gentle acceleration with the RPM wavering up and down slightly as it did so, when I would have thought it should be more like half a second to engage.

On the way home tonight the TC clutch was engaging far more quickly and positively, in fact to the point where it was feeling abrupt, and biting quite hard and quickly when engaging. As the journey went on it felt like the ECU was adapting and it smoothed out somewhat although it remained quick and positive in its action.

What was really obvious though and unexpected is much better acceleration in the 1500rpm range with the TC locked up - the throttle response is much sharper in that range than it has been in a long time, pulling quite strongly with no slip or mushy feel to the acceleration. :)

I've been for a small drive again a few hours later and the behaviour is still the same - a much more positive engagement of the TC lockup and a lot "sharper" and more responsive acceleration at low RPM with the TC locked up, the difference in throttle responsiveness below 2000 in 3rd is night and day from what it was only a couple of days ago.

It's taken about 3 days (albeit a quite small mileage maybe 20 miles) for the change to occur, and it has occurred quite suddenly. It has me intrigued - sticky control valves starting to free up a bit perhaps ? If that's the case I'm even more convinced a good flush and additive (along with another oil change) could be very worthwhile. :)

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by DHallworth »

If the change has made it better, Simon, give Mackie's Transmissions a call and speak to them about a hot flush. It's genuinely worth it and has made a night and day difference to the 5HP24 in a friend of mines Range Rover. He reckons it's the best £150 he ever spent.

David.

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by xantia_v6 »

The more I read about this car, the more I am convinced that it is suffering from low pressure and/or a worn torque converter clutch. After the number of fluid changes you have given it, there is nothing wrong with the fluid, it is just at the marginal point where it can only just transmit power without slipping.

My advice is to stop spending money on it. The scrap value plus a few hundred pounds will get you another car which will not dominate you life in the same negative way.

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by CitroJim »

xantia_v6 wrote:The more I read about this car, the more I am convinced that it is suffering from low pressure and/or a worn torque converter clutch. After the number of fluid changes you have given it, there is nothing wrong with the fluid, it is just at the marginal point where it can only just transmit power without slipping.
That's two of us then...

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Don't give up yet guys :wink:

Worn out torque converter clutch ? That's what I assumed for a few months but I'm not so sure now guys, at least not worn enough to be causing the observed symptoms.

Low pressure ? Yes, in hindsight its quite likely the rail pressure has been low and/or fluctuating and/or the valves controlling the lock-up clutch have been misbehaving. It's a real shame that the Lexia can't measure the rail pressure on a 4HP20 the way it can on an AL4, as any low pressure could have been picked up on right away.

What I didn't mention is that the same day that the TC clutch has started engaging more positively I notice there is quite a bit more "jump" when engaging drive or reverse from neutral, reverse in particular. I can notice the wear in the engine mounts now... :twisted:

As I'm sure you know Jim when the gearbox is in 3rd emergency/hydraulic mode the line pressure regulator runs at the full 15 bars all the time, (instead of ~7 bars most of the time) and that the increased pressure causes it to bang quite hard into drive and reverse, so to me the more abrupt engagement into drive and reverse from neutral is a sign that either the line pressure has increased or the valves are moving more quickly, most likely the former, either way its a good thing.

When I think back the problems with the TC clutch being wishy washy at engaging (as well as slight "flaring" of engine RPM when accelerating at 60mph etc, which I believe is the clutch responding too slowly to ECU commands during engine torque changes) didn't start until AFTER I started doing oil changes.

The original symptoms that made me start changing the oil was a loud groan/shudder when pulling at low RPM.

Here's what I think the sequence of events have been over the last year:

1) The oil was very dirty and old when I got the car, maybe even burnt, a long hard 800 mile holiday trip was the final straw that pushed the oil to the point where the frictional characteristics of the oil were too far out of spec (friction modifiers worn out plus containments) causing clutch shudder.

2) I did 4 oil changes spaced over a month or so which eliminated the shudder due to the cleaner oil and fresh friction modifiers, however on the down side I think the detergents in the oil lifted a lot of dormant muck out of the system and some of it got stuck in the valve block interfering with pressure regulation and control of the clutches, and became gradually worse over the last 6 months.

That's always a risk with doing oil changes on a box that hasn't had any in probably 100,000 miles... which is why some people warn against it. :(

3) The change I did on Sunday may have started to help clear out some of the crud in the valve block. The oil itself might not be that dirty now compared to before but I believe the valve block may still be coated in a thin layer of crud, which is why I'm thinking a flushing agent might be better than just an oil change or a hot flush for that matter.

I don't have any intention of spending £150 on a hot flush as I don't believe the oil is dirty enough to warrant it, and I'm not convinced that just flushing through standard oil will do much more than I've already done with the number of plain oil changes I've done.

I'm going to try the flushing agent and the additive to see what happens. If that does nothing then I might admit defeat...

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Hell Razor5543 »

As CitroJim has made you a damned good offer, I would not be inclined to admit defeat until have let him get his hands on the 'box. If it can be revived, he can do it.

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Mandrake »

Hell Razor5543 wrote:As CitroJim has made you a damned good offer, I would not be inclined to admit defeat until have let him get his hands on the 'box. If it can be revived, he can do it.
I mean admit defeat in fixing it without taking the engine and gearbox out.

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Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Hell Razor5543 »

Fair enough. What worried me was Xantia_V6's comment was to stop spending money on it, and scrap her. I don't agree.

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Post by addo »

Yes; that sort of response should be reserved for parents and troublesome siblings.

Northern_Mike

Re: Xantia V6 broken exhaust (update: and rough low rpm runn

Post by Northern_Mike »

Hell Razor5543 wrote:Fair enough. What worried me was Xantia_V6's comment was to stop spending money on it, and scrap her. I don't agree.

I think this should have been done some ago. It's all very well saying it when it's not your own money, but hell, this car has been a money and time pit and it's still got a dying gearbox and apparently dodgy engine mounts plus who knows what else. Getting it right, even with Jims kind offer is going to take up considerably more money and time, have the car off the road with no engine in it etc.

I've ran old cars for most of my driving life. There always comes a point where you have to say enough is enough and spend no more money or time on it. I think this car is already past that. Scrapping it or breaking it for the useful bits then weighing in the rest plus whatever Simon was going to spend on repairs would buy a good little motor.

It would also have so much less impact on his home life, and once they're sorted and have a bit of cash left over, he can buy another French heap, like I always do.

Now though. . Enough is enough in my view. I'm not being negative, just sensible.

If Simon had a big garage, a hoist, loads of tools and another car, then I'd think differently.

He hasn't, and it's becoming a total ballache by the sounds of things.

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Post by addo »

I think another item would become the focus of similar trials and discontent.