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

[addo]

Was it really moody around the time it got the hot flush?

[Chris570]

Was it really moody around the time it got the hot flush?

I was wondering how long it would take for that joke

[Hell Razor5543]

I blame the stupid plumber!

[Mandrake]

I've got a friend who has a Range Rover with the 5HP24 gearbox in it. That also runs on LT71141.

He took it to Mackie's Transmissions in Glasgow and let them do a "Hot Flush" on the gearbox and says that the difference is unbelievable. Apparently this is the only way to be 100% sure of getting all the dirty fluid out.

David.

What were the symptoms he took the Range Rover in with ? I assume they just insert their hot flush equipment in the loop that feeds the oil cooler thus pumping out the old oil and pumping in fresh oil from a drum in its place as the engine idles, until the oil coming back out is clean ?

I wonder how much he paid for that, I'm betting that it would take at least 20 litres of pricey LT71411 to flush the box considering it holds about 8 litres...plus labour costs...I wonder how well that flushes the torque converter, I'm not sure how much circulation there is through the torque converter when the engine is just idling.

With multiple manual changes each change dilutes the old oil by about 50% since I'm draining out 4 litres and the total is just under 8 litres... so now after 2 changes the old oil will be only 25%, after three it would be 12.5% and four changes 6.75%... judging by how quickly the symptoms improved it looks like it takes approximately 10 miles of driving in between changes to fully mix the old and new oil...

[addo]

http://www.aussiefrogs.com/forum/showth ... vice/page2" onclick="window.open(this.href);return false;

Post 27 pins it, confirmed in Post 36.

Had a C5 break in today with blocked converter, too.

[lexi]

A full flush on a 100k 4hp20 has dubious advantages. Consider the cost. Plus the fact that you cannot get the filter out.
Also the debris that could be dislodged. Be careful of chasing the car with more money. It will be £250 for that flush ? There was a 2ltre auto car on here for £500

You can change ALL of the fluid should you so wish. You connect up to 20 litres (£ 150 on Ebay?) and pump out 2 litre at a time, then replenish with 2 litre, until clean fluid is coming out. The motor can be run for seconds doing this ,or flicked with the starter.

It's going for now anyway, which is good. Even another few months with it would get you some of your spending back........you may get longer.
ATB mate.

[Mandrake]

Don't worry Alex, I have no intention of spending money doing a hot flush on the box, I was just curious how it was done and how effective it is compared to multiple manual partial changes.

I do intend to do a couple more changes of oil in my own time though over the next month and observe the results.

I've been doing a bit more research and also talking to Jim about it in PM and have come to the conclusion that the groaning noise that I've been chasing for the last few months is the torque converter lock up clutch shuddering under load in the controlled slip mode, due to the oil being contaminated with very fine (nearly invisible) metallic dust/particles.

The symptoms are identical to those a guy was getting with his porsche cayman ZF gearbox (which also runs on LT71411) that I posted a link to way back earlier in the thread, he did a full drain and sent the oil to a lab for analysis and found a high concentration of metallic powder (and other things like phosphors) in the oil. This metallic powder could upset the friction curve of the lockup clutch preventing it operating smoothly, thus the clutch becomes grabby making a smooth controlled slip impossible. Needless to say when he changed the oil (he was able to do a full change not a partial change like the HP20) the symptoms went away.

The 2nd oil change is the first thing that has improved the symptoms since they first started appearing. If I'm right about what it is its going to take at least another 2 changes to get the oil clean enough to fully cure the problem - it does still groan sometimes especially when hot, just far less often than before and it now requires a heavier load to do it instead of doing it with a very light throttle. As long as the oil that comes out is still filthy (which it was on the 2nd change) there is still room for further improvement.

The problem with buying another auto to replace it (apart from the missus not letting me ) is yes, its £400-500 for a whole car, but you're just buying into the same problem again - sure that V6 linked earlier in the thread may be running ok now, but who knows what its gearbox history is, its gearbox will inevitably die at some point, and could do so at any time at it has done a similar mileage. Even if it doesn't all the the other jobs on the car have to be done all over again. Sometimes better the devil you know when they get to that age...

Lets face it, changing the oil is dead easy, a bit tedious maybe measuring it all out and checking the level umpteen times, but its an easy job for me to do a couple more times, and if it brings the car back to life it will be worth it and mean that all the other work that went into the car wasn't in vain. That, and I get attached to my cars, the thought of giving up on it recently had me pretty upset, so to see some significant improvement is quite heartwarming.

[CitroJim]

Hi Simon, sorry I've not responded to your last PM or even vaguely intelligently to your most recent posts

At present my brain will not allow me to even read and properly digest the latest news Be in touch as soon as the brain allows

[CitroJim]

The problem with buying another auto to replace it (apart from the missus not letting me ) is yes, its £400-500 for a whole car, but you're just buying into the same problem again - sure that V6 linked earlier in the thread may be running ok now, but who knows what its gearbox history is, its gearbox will inevitably die at some point, and could do so at any time at it has done a similar mileage. Even if it doesn't all the the other jobs on the car have to be done all over again. Sometimes better the devil you know when they get to that age...

Simon, that is so right. I agree 100% and if the worst happens and your box does go pop you know the rest of the car is good and therefore worth sorting out. Just get a cheap Xantia to keep you going whilst you sort out some logistics...

I'd cast around for a spare 'box that's known working and overhaul it ready. A known worker will only need a strip, clean, a filer and gaskets/seals... Plus time of course. You can get away with not needing any special tools as well. Send the TC to Mackie's for an overhaul and you'll be set for the life of the car then...

A nice winter project you could possibly do indoors if the other half can be persuaded to see reason... Swapping 'boxes is then a weekend's work with a hoist and a willing assistant...

[Mandrake]

With the last gasp of good weekend weather for the foreseeable future I decided to do the remaining two oil changes today... I did both of them rapidly in a row with about 20 miles driving in between the two to mix things up. (Normally I would have done the second one the following weekend, but chances of future good weather like today are remote)

So far no groaning noises at all, and I tried my hardest to provoke it, so the groaning noise is definitely oil quality related...the oil that came out still looks dirty, although I am only looking at it in 2 litre pepsi bottles, so it wouldn't take much contamination to make it opaque in that size bottle. When I was pouring it into the bottles it looked a lot cleaner than earlier changes. I'll find some small test tube size bottles to pour a sample from each of the four changes to see what difference there has been.

A slight spanner in the works though was that the engine seems to be very flat with poor low rpm pickup again today. It was like that during the initial warm up drive before I changed the oil so its not oil related, and probably not gearbox related. It didn't change significantly from cold engine to hot nor did it change after the oil changes.

Like before, when I put my foot down at low rpm in a higher gear I get an unusual amount of "boom" which is either induction noise or boom from the exhaust, I can't quite make up my mind, but I think its exhaust. On the flat the pickup from low rpm is very poor in 3rd, up an incline it just will not pick up at all until it kicks down a gear at about 70% throttle. So whatever it is is back again, and it was perfectly ok as recently as yesterday, and it has been fine for a couple of weeks.

Are we back to thinking intermittently blocked cat again ? Would a blocked cat cause an unusually loud boom from the exhaust when putting your foot down ? I would have thought the opposite. It sounds a bit like the boom you sometimes get on the overrun when there is no combustion happening due to fuel cutoff, but louder. Is there any way an intermittent MAP sensor could cause poor pickup and boom due to lack of fuelling ? A bit mystified by the "boom" which only seems to be there when its not running well...

Another possible clue, but today its also doing the almost stall and recover routine after starting a warm engine where the revs dip down and recover a few times before finally settling down. It has NOT been doing this when the engine has been performing well. Possibly related ?

I start my new job tomorrow and will be catching the train to work so the car may not be driven again until next weekend, will be interesting to see what condition it is in then.

[Mandrake]

A nice winter project you could possibly do indoors if the other half can be persuaded to see reason... Swapping 'boxes is then a weekend's work with a hoist and a willing assistant...

If I could find somewhere to live that had a garage I could park the car in and work on it over a few weeks/months I would consider working on the gearbox, until then its just a pipe dream though.

[Hell Razor5543]

Do NOT give up Mandrake. The biggest problem you had was a large multitude of lesser problems. You are resolving them one by one, and you are getting there.

When you have 1 or 2 problems, they are easy to diagnose. When you have several, they can either mask or amplify each other. I have (once) had the same situation in computing when I had a PC with 5 problems, all bouncing off each other. I stripped the PC down to minimum configuration (which removed 2 problems for now), and the remaining problems then stopped bouncing and became obvious. When I resolved them, I started to bring the PC back up to full config step by step, and was able to fix the last 2 problems.

I have no knowledge of the V6 Xantia, so I cannot help with the problems. All I can offer is encouragement. With the effort you are putting in, she will drive again, and as Citroen intended (or better).

[addo]

How much of a mongrel to R&R, is a V6 exhaust from the rear bank to centre muffler?

[Mandrake]

Judging by the state of the spring loaded bolts on the flexible joint between the cat and the manifold (rusted solid) it would be a right PITA. I wonder if the fittings on that flexible joint are readily available...I don't think I would attempt to remove it without a replacement set of springs bolts and washers at the ready.

[RichardW]

Fitting kit available from Citroen for £25 - it's a standard arrangement, so should be available from factors etc - but the only bit that won't be recoverable is the nut and bolt, and this can be substituted - the side of mine that I had to cut off just has a piece of threaded bar in it with a nut on either side - been there 2.5 years quite happily.....