Hi,

We have spent most of the last six months trying to resolve cooling system leaks on a friend's 2005 3.0L X-type.

Problem I now have is that the rectangular Thermostat seal (C2S11282) will not reliably seal against the aluminum flange on water pump auxiliary drive. It appear that the join 'opens up' at one end, and it's not possible to close the gap with the two bolts that hold the flanges together.

This problem first started when the top radiator plastic hose split while my friend was away from home. That was replaced by a garage near where the car overheated, and it drove home without incident. A couple of weeks later, the car overheated again and it was very clear that the plastic flange on the T-piece was not sealing against the aluminum flange on the engine. It looked as if one of the two bolts wasn't tight - there was about 1/4" gap at one end of the flange, and almost no gap at the other end. Initially I assumed the shop had failed to tighten the bolts, or had installed the part incorrectly. However - nothing we could do would close that gap up with the flanges parallel (tightening/loosening the two bolts, removing and refitting the entire hose assembly) - as you tightened it, it would always open up at one end.

We wondered whether the new hose assembly was the problem, so bought another (this time Jaguar OEM) and fitted it. That appeared to seal first time, even though I could see absolutely no difference between the part. There were no leaks - for about two weeks. :-(

Then the top of the radiator cracked (plastic top tank). It was clear that all the movement of fitting/refitting the hose had stressed the top driver's side mount (the hose there had been very difficult to remove). To be fair, the radiator plastic was probably brittle from age.

Fitted a new radiator (without removing the top hose, or touching that flange joint) - just disconnected the top hose from the radiator near the battery.

Since then the car has been slowly loosing coolant...but couldn't track it down. Finally today discovered that there is a 'tiny' leak at that flange, and it has again opened up at one end (the end closest to the battery), though only by about 1/8". It's perhaps worth noting that it only leaks if you have got the car up to temperature and rev it above about 2000 RPM.

The aluminum flange itself appearedto be clean when I fitted the hose (there are others who have reported the surface being corroded). Has anyone else had this issue? Knowing how much of a pain it is to remove remove it again, and the risk of causing damage to the other plastic parts I would really like my next attempt to be successful....

Appreciate any thoughts anyone may have on this...

Thanks
Steve

(I also have to say that the use of plastic everywhere on the X-type cooling system is a huge design issue - and even the design itself is poor. I'm pretty certain that having three bolts instead of two on this flange would have prevented any leaks.

About 2 weeks ago I have had the water pump housing (this is where the aluminium flange is a part of) removed.
Yes, definitely: That surface of the aluminium was utterly corroded on my X-Type.
I did not have a leak there before I took that apart, but I was already afraid that I would be facing a leak there, once I reassembled it, because I already noticed that the surface of that rectangular Thermostat seal (C2S11282) was extremely rough, as it adapted itself to the utterly corroded flange.
Hence, since I do not have such a seal at hand at the moment, I did a bit of witchery and achieved that that seal seals now (part of the witchery was to restore the corroded surface with liquid metal...)

So I know what seal you are talking about, but I am not clear about your problems...
Did you buy a new Thermostat Seal C2S11282?
You did not have an corrosion issue on that opposing surface?
I do not understand how you can have issues with a gap / the 2 bolts / the 2 nuts...
The issue I had of how to reach those nuts in the first place.
In the end I used long and short (long for the lower, short for the upper nut) 13mm-sockets, and a little ratchet on the long socket directly and a joint a several extensions for the upper nut (from underneath).

Another possible source for coolant leak (I mean the options there are plentiful, like the reservoir (cracked)), would be the round seal on the other end of the water pump housing, where it connects to the black metal pipe/hose. This seal could also be leaking AND I can also imagine that the metal pipe itself can rust through and leak! Or the water-pump seal, of course and the coolant leaking at any of the 3 just mentioned places could wander down to the square seal, so that it would look like the square seal leaks, even if it does not.

Thanks for the reply Peter - I saw your thread on the various leaks; some useful photos there!

Yes - the problem is that seal - C2S11282 - I can see a spray of antifreeze coming out of the 'battery' end of the gap between the two flanges
I have changed the seal (twice) - with each of the top radiator hoses (both came with the seal)
You are correct that those nuts are difficult to get to....especially the one closest to the center of the car.

The problem I have is that the two parts of the flange don't seem to stay parallel - there is a visible gap at the end closest to the battery. If I tighten the nuts the issue seems to get worse (and, of course, if I loosen them the joint isn't sealed at all). Because there are only two bolts (not three or 4) that appears to allow the joint to twist....

The red arrow on the photo shows where the crack opens up - and the leak is.

-Steve





Crack where X-type top hose flange doesn't align with water pump

I, too, don't like various materials used by Jaguar - the plastic in you already mentioned above, plus plastic cam covers on the X308 and Magnesium/Magnesium-Alloy cam covers on the 2004 3.0L S-Type (note that magnesium is the sacrificial element, where magnesium cam cover and the aluminium engine react electrochemically and the cam cover dissolves over time...)

I am not sure, if the details of how exactly I fixed my leak at the point of the big square seal, do help you, but just in case:
Currently I do not have a new square seal at hand, hence, I solved it like this:

This is where the square seal goes into (the seal is not in position on this picture).


When I had that leak there (after I already flattened the opposing flange with liquid metal) and happened to have a lot of thin black rubber O-rings in my garage: CS:2mm, OD: 72mm. I placed one of them into the groove there the proper seal would normally sit - just to check size, and it was OK (see above).


I them removed that O-ring again, and placed RTV high temp silicone into that gap, then again that O-Ring, then another layer of RTV, and then the original (old) square seal, with that side, which was slightly deformed (due to its former contact with the corroded surface) now facing inwards - towards the RTV:- so that the remaining flat surface would face the flange.


And on the top outer new surface of that square seal, I tried to put as little RTV as possible. I then screwed the part back into position and no leaks. The idea behind all this: The original seal would have been pressed onto the flange for many years, and therefore would have lost a bit of depth. I made up for that lost depth by stuffing the O-Ring in first. It certainly is not the most beautiful solution, but it is a possible solution. And I still do not understand as to why you have the problem with that gap - maybe that here is an idea for you as well?

I'm currently thinking of another route (following a suggestion from a friend, also with an X-type). He noticed that the original 'top hose' T-piece has a join in it, but the new replacements all seem to be molded as one solid piece (even if the online picture shows it as two pieces). We're wondering if the one piece molded versions have a slight 'twist' in them that causes the misalignment, perhaps over time.

I'm considering cutting the top hose, and joining it again (with rubber hose) in a similar way to the original; that might take some stress off the flange. But I'm going to think about that carefully before doing it!!

-Steve

Do you have a picture of that? Are you talking about the part, which is in my first picture above? Is that different? Yes, I heard many times before that there could be a leak in the T-piece on the X-Type, but I was never sure, which part they are talking about.

I understood before that you are sure that the coolant leaks out of the square seal... But if not:
Another place, where the coolant could escape big time is the secondary outflow from the water-pump-housing - the main outflow has that round seal and goes to the black metal pipe (opposite of the square seal). Close to that main outflow (pointing towards heavens) is a smaller outflow with a rubber hose and a hose-clamp attached - I actually forgot the first time to re-attach that rubber hose and the coolant came just pouring out. But if that rubber hose is damaged or you forgot the hose-clamp, there will still be a considerable leak there.

Yes - it is common that the T-piece splits or cracks, and leaks under the airbox. That is why the 't-piece' (top radiator hose, part C2S43430 was originally replaced.
The original part (as fitted to the car) came in three pieces, with joints that gave some flexibility as you assembled it, and perhaps reduces strain on the flange joint to the thermostat (and also made it easier to install)

I've now bought two replacements, and both have come in one piece, even though the web sites all show a 3-piece part. The photo below is from Moss Motors ( https://mossmotors.com/c2s-43430-top...rmostat-x-type ), and I've marked it up to show the joints (which are now replaced with a permanent molding, making the whole thing a lot more ridgid). I guess it's possible that some folks had problems with leaks at the joints so they removed them?

I am absolutely 100% certain the leak is out of the flange joint - I took a couple of photos, but you can't really see due to the spray of droplets hiding the hose!

I'm not sure why I can't get it to seal, but am wondering if the absence of this joints is somehow related....


Shows C2S43430 and location of joints which used to be on this part.

https://www.jaguarforums.com/forum/x...t-loss-207203/

I'm confused a bit by your description. The "T" that gets a micro crack and leaks is indeed plastic. The other parts are rubber hoses that clamp onto that plastic "T" that is vertical (note my comment and picture of swelled old hose vs new hose size in above link) with the built-in thermostat at the bottom.

@ the fixer: I think I understand now, what you are saying.
To start with: The picture in you last post seems to be identical with my part, which I showed as first picture in my set of 4 picture just a little bit above., obviously, to the left and to the right of my part there will be the rubber hoses (clamped on), also shown in your picture.

So, what you are contemplating about now is the following - if I get that right:
You did have as original part that kind of part, which you show above (photo from Moss Motors). But when you ordered replacement, that's not the kind of part you received, but you received an updated version, which cannot be taken into pieces like the part shown above. And your train of thought is now that that is not the only change on that part, but that they also modified the connection that goes onto the flange of the water-pump-housing - and they changed it to the effect that it just will not fit nor seal anymore...

Well if you can, then sent a picture of THAT new part, which you actually have there now.
Other than that: I would strongly recommend (as I would do in general for everything): If you receive a new part, hold it next to your old part and look very carefully, if everything is identical. In your case: If the exact shape and dimension of the connection towards the flange is the same and if the angle of that surface is identical of how it was on the old part.

Note aside: I once received a replacement "hose-unit" for power steering of the S-Type in the mail. When I unpacked it, it looked all alright. When I removed the old part and wanted to fit the new part, I could not figure out how to fit that, hence, I removed the new one again and I held it next to the old part - ...well, it was different... - and then I figured out, why: I ordered the part from the US. I am in Australia. Or in other words: I ordered the unit for the LHD, and I have a RHD, and those parts are not the same. After further investigation, I found out, that it is impossible to buy the correct RHD hose-unit anywhere - thus, as there was nothing to loose and the biggest part of the costs for that part from the US were the postage costs anyway, i.e. return was not an option...:: I attempted to do my usual "witchery" again and buy carefully bending the LHD hose unit, I transformed it into a RHD hose-unit. Problem solved. In summary: Always check very carefully, if the new part is an exact copy of the old part. I would not really expect that there is a LHD and a RHD version of your trouble part, but better check that as well...

Thanks Peter,

At last I've been able to get back to this, and now have it in my (very cold garage). I've removed the air cleaner so the issue is easier to see, and applied about 5 or 6lb pressure from a radiator pressure tester. At that point the leak becomes very obvious (see the orange fluid leaking below - if the pressure gets above about 5psi it's pretty much spraying out.

Here's the issue - both the bolts that hold this flange are tight (and there is no discernible gap at the corners where the bolts are (you can see that on the left, and it's the same on the opposite corner, which is out of sight in this photo). However, the flange appears to twist (?) or bend, so that it is leaking at the corner where you can see below. I can't see any way to tighten that up. The gap appears to open up as more pressure is applied to the system.

Note that there is a steel plate on the plastic flange (on the side where the nuts are) - you can the edge of it in the photo. I think this is supposed to help hold it flat (rather than stressing the plastic). I had hoped the original shop that had worked on this had forgotten to replace it, but as you can see it is in place (it's at the lower end of the flange visbible in the photo)

Now have a clearer picture, I'm hoping that someone out there has had the issue - and knows how to solve it!!

~Steve










Leaking flange on radiator top hose

Ok, I fully understand your issue now.
I can see the metal plate - and here I have a nice picture from mine, where the metal plate is even more obvious:

That's that plastic flange build in without the water pump housing blocking the view.
Also note: In my picture that rectangular seal is pretty much prone lurking out of the plastic flange groove. If it looks like this, I just do not know, why you could have that leak.
Sure, 4 bolts (one on each corner) would be better, but why do most X-Types with 2 bolts not have that leak? I remember you writing that you have a brand new rect. seal in there. Hence, you SHOULD NOT have that leak.
Note again my picture above where I reused an old (flattened over time) seal, which really "had it", but with that trick (RTV & an big O-ring with a small x-section under the rectangular seal) made that old seal really lurk out prone of the plastic flange again, and I do not have a leak.

Hence, the only thing which comes to mind: Did you take pictures back then, when you placed the new rectangular seal into that plastic flange (I always take picture, when I do something on the Jags - it helps me to put it back together again, after taking it apart (and also I write DIY guides, when I find the time). Or if you did not take pictures: Is your memory good enough so that you can confirm that your new rect. seal was lurking out of the plastic flange as much as you can see it on my picture? Cause, if not: Is therer any chance that your new rect. seal is somehow the wrong part? Did you compare the old seal with the new seal?

And what was the story about the opposing metal surface (of the water-pump-housing) on your X-Type? Flat surface / no damages?

Thanks Peter!

All good questions above, and I'm not totally sure of the answers. That's because the first time the T-piece was replaced was by a garage some distance away (and it was replaced because the plastic on the t-piece had split). A couple of weeks later it overheated again.

My friend then brought their car to me, where I diagnosed the flange leak initially. I ended up replacing the t-piece (because I thought that might be the cause), and the gasket. It seemed to be sealed ok.I could NOT get the T-piece the garage fitted to seal. I assumed it was faulty manufacture.

However, the radiator was then replaced when it cracked at the top (without this joint being separated), and then the joint appeared to start leaking again (the radiator was removed by someone else)

I am wondering if the flange connection was stressed or twisted during the radiator removal and replacement. Someone else has also suggested that perhaps there is a bad engine mount (which could put stress on this at the engine moves)

My current plan is to separate the joint and remove the T-piece again, very, very carefully examine everything (mating surfaces, gasket etc) and see if I can get either the current T-piece or a new one back in with the flange tight all the way around. I'd prefer not to use RTV, but I do think the idea of the extra O-ring is a good one...

I will report back..

-Steve

OK, but I am somewhat skeptical, if an extra O-ring WITHOUT RTV could seal at all - it's the combination of extra O-ring (a thin one) and RTV, which worked for me...

Hi Steve,
I just revisited this thread hoping I would find a P/N for a seal, hoping I would have written it down here - apparently I did not - anyways:
While being here I caught another glance of the last picture you have send...:

...well, I can't be sure by lost looking at this picture - you have to confirm my suspicion by looking closer at your part - preferably while the engine is running, and as the battery is probably in your line of view: Get yourself an "endoscope camera" (that is a tiny camera at the end of a bendable cable for your mobile phone. They are ridiculously cheap: About AUD$5 on aliexpress). And while the engine is running, have a look, WHERE the coolant really comes out - because I have a little suspicion: Look inside the red oval above: THAT could be a crack in the water pump housing.... - and if so, the escaping coolant from there could just drip down towards the flange giving the wrong impression that that leak is there....

PS: It is also possible that that crack continues around the corner and that the coolant is leaking from behind the tensioner pulley - and that would be really hard to spot...

I have a little extra info for everyone having coolant leakage issues:
While it is probably not the solution for the problem at hand here, I have already mentioned in my initial reply above:
"Another place, where the coolant could escape big time is the secondary outflow from the water-pump-housing - the main outflow has that round seal on the other end of the water pump housing, where it connects to the black metal pipe/hose."
I did not know the P/N of that seal for sure - now I know:

Someone may have a leak there and is desperate to find that seal - thus: It is XR85431

I had spend a very long time looking for it, and the few available sources had ridiculous prices. But then I thought: It does not make any sense, that britishparts does not have that seal, as it is used in X-Type and S-Type. Hence, I contacted britishparts directly. They have it, and Vicky has no idea, why does not come up, when your look for it on their site....
Their price is 2.28 Pounds (w/o VAT). But as usually their postage costs are the killer, but I just ordered a whole box full of seals from them.
And I noticed they they still do not list XR85431 "Gasket-water Sprout" on their site, hence, it you want to buy it, you have to contact them and ask for it....

Just FYI: thought I'd look to see Best deal in UK for that seal and it's 83p from Britcar.com (as of today)
Cost of a letter £2.80 and delivery in 5-7 days plus the customs forms...
Not sure it helps anyone - just feel the need to share

Thanks, PCJags,
I did not know this parts-supplier yet. Good to know. I bookmarked it.