Simon's new Xantia V6 and Leaf blog

Tell us your ongoing tales and experiences with your French car here. Post pictures of your car here as well.

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Mandrake
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Re: Simon's new Xantia V6 blog

Post by Mandrake »

RichardW wrote: You won't need to remove the upper housing as it is behind the lower one - the lower one appears to fit over at, where the seal is shown as 6 on Mike's screen shot (and you can see it in the 3rd pic in the guide you linked). I might be tempted to get an O-ring for here, otherwise it's bound to tear on removal!! Only £1.49 (P/No 134045)
Well that's the parts ordered from Citroen Glasgow - they claim they'll be in tomorrow which is pretty good, and the coolant from carparts4less should be here on Friday. We'll be out on Saturday afternoon for an appointment that can't be postponed but it looks like I'll be doing this job on Sunday morning! Fingers crossed I won't run into any major snags as I don't like to start these kind of jobs on a Sunday instead of a Saturday, but I don't want to leave it another week and the following weekend is forecast as pouring rain anyway, making it at least 2 weeks delay if I don't do it on Sunday. Weather for this sunday looks "OK".

The thermostat, gasket and the o-ring you suggested should have added up to £45, but I got bitten by the "minimum order quantity" monster. :roll: They say minimum order for the £1.49 O-ring is 5 and minimum for the £16.16 gasket that slides over the thermostat body is 2! :( So that pushes the total price up to £65.... oh well, at least I'll have some spares I suppose, and it will still be costing me far less than paying someone else to do it... If anyone needs one of those surplus gaskets or o-rings once I've finished the job let me know! :lol:

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Stickyfinger
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Re: Simon's new Xantia V6 blog

Post by Stickyfinger »

My car was quite mucky down there, maybe prep the area with some gunk/cleaner the day before ?> not the best area to fit stuff without getting crap into joints etc if it is dirty

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Mandrake
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Re: Simon's new Xantia V6 blog

Post by Mandrake »

Stickyfinger wrote:My car was quite mucky down there, maybe prep the area with some gunk/cleaner the day before ?> not the best area to fit stuff without getting crap into joints etc if it is dirty
Good idea. I was thinking of doing some of the prep work (but not enough to disable the car in case the weather packs in) on Saturday afternoon after we get home to speed the process on Sunday.

I think I have an unused spray can of stuff called "Gunk" or similar that does what you describe! :) I'd just need to find it...

elma
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Re: Simon's new Xantia V6 blog

Post by elma »

Mandrake wrote: The thermostat, gasket and the o-ring you suggested should have added up to £45, but I got bitten by the "minimum order quantity" monster. :roll: They say minimum order for the £1.49 O-ring is 5 and minimum for the £16.16 gasket that slides over the thermostat body is 2! :( So that pushes the total price up to £65.... oh well, at least I'll have some spares I suppose, and it will still be costing me far less than paying someone else to do it... If anyone needs one of those surplus gaskets or o-rings once I've finished the job let me know! :lol:
I'll probably be needing those soon, pm me details and I'll sort you out some money.

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Re: Simon's new Xantia V6 blog

Post by RichardW »

I hate it when they do that.... Can sort of understand it for small O-rings and the like - but min order for crank shaft pulley bolt for a 1.6HDi that you are meant to replace when you do the belt is 2! WTF would anyone want 2???!!!?? *

Hope the change over goes OK Simon.

* actually I did - as I knew the 307 would need doing eventually. Now, I wonder if I can find it.....

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Mandrake
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Re: Simon's new Xantia V6 blog

Post by Mandrake »

Well that's all the parts and coolant arrived and ready to go for Sunday, weather report for Sunday is oscillating between rainy and fine! #-o

On Wednesday/Thursday the thermostat decided to stick shut most of the time. From that I learnt that you can drive about 8 miles from cold with no radiator flow before the engine reaches and starts going past normal temperature! I also learnt that the heater on full blast can almost keep up with the heat generated by gentle 30mph driving...so anyone who experiences a stuck thermostat keep in mind the trick with the heater - it might get you home a bit faster than stopping for 15 minutes every 5 minutes!

On Wednesday after I'd got home after the temperature seemingly being normal I jumped out and checked the radiator to find it stone cold, thinking I'd give it one last chance to see if it was an airlock I opened the cap with the intention of letting it idle for a few minutes (remember indicated temperature was under 80 on the gauge) and initially there was only a tiny burst of normal pressure out the cap and calm water, but in just a few seconds it decided to boil.

I didn't realise until later but my Dashcam caught the whole thing! :rofl2: So here it is for your viewing entertainment and as a cautionary tale of what not to do.... #-o





No sooner had I opened the bonnet further when I noticed in just those few seconds it had started boiling - you can literally see me run to turn the key off, and the coolant spewing out, but....too late. I lost a whole expansion bottle worth of coolant in that few seconds and after topping it back up I had to hose down and then dry the whole area under the bonnet so as not to leave anything that would corrode connectors etc.... #-o

By the way, the beeping in the background afterwards was the smoke alarm in the house being set off by cooking so completely unrelated, but very well timed. :rofl2:

On Thursday after getting home with a mostly (completely ?) stuck thermostat I thought I'd try giving the thermostat housing a good thump while it was hot - a standard large flat file is perfect for the job - you can just see and reach the bulge of the thermostat housing down between the engine and air filter box and rap on it. After doing that the radiator started getting warm immediately and funnily (or annoyingly depending on how you look at it) it has behaved absolutely perfectly all friday with no overheating. [-X

So this does give me more confidence that a sticking thermostat is indeed the problem. It will be interesting to see if it is sticking on the gasket (the new one of which is very hard, almost solid BTW) or whether the insides of the thermostat itself have gone rusty.
Last edited by Mandrake on 28 Jan 2017, 11:29, edited 2 times in total.

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Skull
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Re: Simon's new Xantia V6 blog

Post by Skull »

The fact you've now got flow to the radiator after jarring the thermostat loose is a very good indicator that somewhere in there is the problem ... nice trick 8-) Good Luck

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CitroJim
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Re: Simon's new Xantia V6 blog

Post by CitroJim »

All the best for clement weather tomorrow Simon and I'm most keen to see the state of the old thermostat!

Good tip about bashing the housing to release a stuck thermostat ;)

I'm almost sure the adding of Forte was just a coincidence as my first V6 had a cooling system full of every sort of rad sealant you could think of and whilst it blocked the transmission cooler it never upset the thermostat...

I believe you have been the victim of horrendous bad luck...

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Stickyfinger
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Re: Simon's new Xantia V6 blog

Post by Stickyfinger »

My bet will be a little bit of crap has dislodged.....nice trick.

If there has been a correct % solution of additive (it is both Anti-freeze & corrosion inhibitor) there should be no "rust". The internal metals (any) should had a dark grey/black colour.
If there are red/trump-orange deposits, then the additive % has been incorrect.

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Mandrake
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Re: Simon's new Xantia V6 blog

Post by Mandrake »

CitroJim wrote: I'm almost sure the adding of Forte was just a coincidence as my first V6 had a cooling system full of every sort of rad sealant you could think of and whilst it blocked the transmission cooler it never upset the thermostat...

I believe you have been the victim of horrendous bad luck...
I think you're right Jim.

In hindsight I think the thermostat has been partially seizing for quite a while, because the temperature has fluctuated more than it probably should have for the same driving load.

Eg sometimes when cruising at 30mph it has shown an indicated 85 and yet other times it might drop as low as 75 and stay a bit on the low side in the same conditions. I bet the thermostat has not been sliding smoothly for a while, perhaps due to rust induced friction. Therefore it takes a significant increase in temperature for it to overcome its movement friction and "jump" to a new more open position, which can then lead to it running too cool for a while.

In other words it was temporarily sticking at various partially open positions. The only thing that is new recently is that sometimes it has been sticking in the completely closed position so the radiator couldn't get any flow at all.

Changing the thermostat was actually already on my to do list (or wish list lets call it!) because I wasn't convinced that the temperature regulation was quite as good as it should be, but once again a deterioration of a probably pre-existing problem has forced itself to the front of the queue! ;)

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Re: Simon's new Xantia V6 blog

Post by white exec »

Look forward to seeing some pix/video of the old 'stat being given a saucepan workout, Simon. Hope Sunday goes well.

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Mandrake
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Re: Simon's new Xantia V6 blog

Post by Mandrake »

Well I spent about 4-5 hours on the job today but its still not finished, so I've had to take tomorrow off work to finish it as that is the last non-raining day for quite a while. :?

Changing the thermostat on this engine is the most unbelievably, unnecessarily difficult job imaginable. [-X The amount of stuff you have to remove to get the damn thing out defies belief. Aside from the obvious suspects like the air filter box I also had to remove:

1) Air filter sock support.
2) Main steel supply pipe from the pump into the pressure regulator (I only removed it at the pressure regulator end and removed most of the mounting supports for it so it could move it out of the way enough)
3) Mounting bracket for the gear selector lever so that one of the thermostat bolts could be removed.
4) Loosened the two bolts that hold the plate beside that to tilt the plate out of the way a bit
5) All the wiring loom up around the throttle plate area had to be completely extracted to make room to get a screwdriver in to undo the hose clamp on the smaller of the two coolant hoses at the rear of the housing, which was a complete pig to get the hose off.
6) A curved black bracket down on the right hand side of the thermostat housing has to be bent out of the way to get at another bolt it hides, (wtf ?) and that bolt is at a depth that is too deep to reach with an offset crank spanner, and too shallow with the clearance that is available for a normal ratchet an socket extension. I had to come up with a very improvised solution to get that bolt in and out, consisting of a deep reach socket, a universal joint drive and an extension bar used in place of a ratchet!
7) The thermostat was stuck fast in the side of the block so I had to try to remove the housing past the thermostat, which gives far less clearance than refitting it with the thermostat sitting in the housing - but it JUST possible to do this, and I mean JUST. [-X

I finally got it all out and although I haven't got it back together and tested yet (reassembly is about half done before I gave up for the day) I believe I've found the true cause of the problem. As soon as I got the housing off I noticed this:
Image
The picture doesn't do it justice - it's a hard white, rough lump on the side of the thermostat at the end where it would be trying to slide through the gasket. There are actually two of them about 120 degrees from each other, only one is visible in the picture.

Under the gasket in the housing there is a ledge divided into three parts that locates and supports the gasket. There is a minor design flaw IMHO in that the diameter of the ledge is only JUST slightly bigger than the inside diameter of the gasket, so the clearance between the stainless steel cylinder of the thermostat supported by the gasket and this alloy ledge is ridiculously small - I'd say only about 0.1 - 0.2mm clearance at most.

So what has happened is two of these ledges have corroded and pitted leaving both pits and raised bumps of hard aluminium oxide, with the bumps actually scraping on the stainless steel cylinder as it moves. On one of them with the gasket in place the alloy ledge sticks out visibly proud of the gasket. It's difficult to see the corrosion in this photo (gasket removed) but I've highlighted the ledges that are corroded and pitted:

Image

And here you can see the very obvious smooth mark where the oxide has been rubbing against the thermostat cylinder, along with the oxide bump at the end:

Image

That's not something that has only started happening in the two weeks since Forte was added, however, it does look like the Forte built itself up on the lump of aluminium oxide that was embedded on the stainless steel cylinder making the bump even bigger - it may have tried to "seal" the gap between the two contact surfaces and this was the final straw that took it from rubbing and sticking slightly to jamming shut altogether. Some of the bump rubbed off quite easily - possibly Forte, but what is left is hard and embedded enough that it won't come off with a fingernail.

If there had been no corrosion Forte would probably have been OK, (although I'm not sure I would risk it knowing what I know now, if the state of the thermostat was unknown) and I also believe that had Citroen given just a bit more clearance between the alloy ledge and the thermostat then a little bit of corrosion would not have been able to expand the ledge until it touched the cylinder. They could have easily given it 0.5mm to 1mm of clearance as the gasket is very hard and strong and the ledge is only there to locate the axial position of the gasket - it doesn't need supporting right out to within 0.1mm of the edge in my opinion, so I consider it a minor design flaw.

My solution was to carefully file all three ledges back with a rotary drill file attachment so they're recessed about 0.5mm behind the gasket, so that there is no possibility they can come into contact with the cylinder, even if they were to corrode further. So hopefully this won't happen again!

I have the thermostat housing back bolted in place but the rest of the grunt work of reassembly and of course filling, bleeding and testing is still yet to be done. Fingers crossed that goes to plan tomorrow. [-o<

As for the saucepan test - the new thermostat opens at 82 degrees as specified and opens about 10mm by about 86 degrees. The old one starts to open at about the same temperature however only opens about 7mm and not until nearly 90 degrees - so it works, but it is "lazy" and doesn't open as much.

To be fair, to get it out of the side of the block I had to twist it and lever it out by the gasket so the innards are now slightly bent so it may not be working as well as it once did! I didn't have much choice though as it was really stuck hard in the engine block, even though no gasket sealant appears to have been used. (I didn't use any either - the rubber flange on the edge of the thermostat looks perfectly adequate by itself!
Last edited by Mandrake on 29 Jan 2017, 23:12, edited 3 times in total.

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Mandrake
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Re: Simon's new Xantia V6 blog

Post by Mandrake »

elma wrote:
Mandrake wrote: The thermostat, gasket and the o-ring you suggested should have added up to £45, but I got bitten by the "minimum order quantity" monster. :roll: They say minimum order for the £1.49 O-ring is 5 and minimum for the £16.16 gasket that slides over the thermostat body is 2! :( So that pushes the total price up to £65.... oh well, at least I'll have some spares I suppose, and it will still be costing me far less than paying someone else to do it... If anyone needs one of those surplus gaskets or o-rings once I've finished the job let me know! :lol:
I'll probably be needing those soon, pm me details and I'll sort you out some money.
Sorry elma, but I ended up having to use both gaskets. It wasn't until I had fitted the new gasket that I noticed one of the ledges under the gasket was visibly sticking out proud of the inside of the gasket, and it is not possible to get the gasket back out again without destroying it, so I was forced to fit the second gasket after filing back those rough edges in the housing! :?

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Re: Simon's new Xantia V6 blog

Post by RichardW »

That's a right git, Simon - I'm beginning to think this car doesn't like you, given the fight the ball joint put up, and that we couldn't get the bolts out of the brake caliper!

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CitroJim
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Re: Simon's new Xantia V6 blog

Post by CitroJim »

Simon, it is a hell of a job isn't it :twisted: The word 'hell' was chosen with care...

Most interesting as to the reason and it is good you found a definite problem.

I'm wondering if the car, having been little used in it's previous life and low mileage, went a long time between routine coolant changes and thus allowing corrosion to build. The car may well have been subject to long periods of disuse and this may too have contributed.

You're right that the design could have been a little better. That's surprising for the ES9 as all else is such a beautiful piece of engineering.

All the very best for the big reassembly today!