WHICH COOLANT?:

It took me a long time to investigate, which coolant to use. The S-Type owner’s handbook actually helps – it says: Use coolant with Ford Spec WSS M97B77 and change every 5 years. The sticker in the engine compartment says WSS M97B77-D more accurately. This is normally the red/orange coolant (definitely not green!). I live in Australia, and here the best coolant comes from “Nulon”. This may not be available overseas, but I can only go by what we have here. I use the concentrate and I use more coolant than distilled water in the mix. The red Nulon concentrate specifically states that it fulfills the WSS M97B77-D requirements and it states that it is good for up to 8 years. But Nulon also has a new product on the market: “Nulon One”, which is YELLOW and is supposedly good for 10 years and it also fulfills WSS M97B77-D. I called Nulon to confirm this, but they recommended doing a coolant change on that S-Type every 5 years, regardless, if I use red or yellow. But one thing is for sure: Never ever mix different kinds of coolant (especially not green and red).

COOLANT CHANGE / COOLANT FLUSH:

When I change coolant, I do a coolant flush. If you happened to have used the wrong coolant in your S-Type or if there was a mix of red AND green, the flush needs to be done anyway. I do the “flush” like this: Draining by opening the valve on the bottom of the radiator, when nearly done, I apply a bit of air-pressure from the filler on the top (I put a suitable big cap with a little hole over my air-gun) to drain it even more, then I close the valve and fill the system up to the top with filtered tap-water (0.1 micro-meter tap-water-filter), and let the engine run for a few minutes with heater fully on, I do this “drain and fill” 3 times. If you should happen to notice (like me) that the heater does not get warm at all, it means you have a problem, which needs solving before you fill in the coolant. A usual suspect would be a faulty valve (which does not let the hot water thru to your heater in the firewall). That valve it located under the right headlamp. That valve and it’s electrical connector are “perfectly” positioned to get permanently soaked in coolant, if there is a leak on the expansion valve or its outflow (looks like someone at Jaguar failed to do an FMEA!). So, obviously, if you have problems with your valve (or heater), check for corrosion on the valve connector. Also: The heater apparently does not want to operate properly, if the coolant- (or water-) level is too low. So after 2 flushes, the water was already pretty clean, but the heater did not work. On the next day, with fresh water, I tried again, and suddenly the heater worked and the clean water was suddenly very red again, which tells me that the valve was stuck for some reason, but after those 2 flushes on the day before and after being surrounded by clean water overnight, the valve had a change of heart and worked again. This is why you do the flush. And with the engine running with heater on: All the coolant in the heater-pipes get flushed as welll. So after a total of 4 flushes with filtered tap-water, I did a fifth with “my kind of condensed water”: This is the water, which my dehumidifier in the house produces. I don’t think that this is any different from the bought condensed water. After draining that I finally filled 5L of the yellow Nulon One into the reservoir, as the total amount of fluid in the system is supposed to be 10.4L. After those 5L coolant I may have been able to fit another 2L in there – bit by bit, with the engine running. You’ll never be able to empty the system completely, thus, a few liters were probably still in the system (hence the “flush” is a good idea). The day after filling up the newly fixed leaky system with coolant, there was quite a bit missing again in the expansion tank - and I feared already that I overlooked a leak, but it looks like it just takes some time until all air-cavities in the system are finally filled with coolant... Thus, all good.

S-TYPE COOLANT LEAKS AND HOW TO FIX THEM:

I am pretty sure I had leaks at 3 different locations at that 2004 S-Type V6 3.0L, which I bought recently. All of them were basically not obvious at all were difficult to find.

0.) EXPANSION TANK: After a quick look and before taking the engine apart, I thought it could be the coolant reservoir (expansion tank) and I ordered one. Well, it wasn’t that and I have a spare one now, but if you happen to be looking for one: I was searching for the expansion tank for the 3.0L S-Type. The listings on ebay make you believe that only P/N C2Z13764 suits the 3.0L, while the much cheaper P/N C2C41899 is apparently only for the 2.5L and 4.2L version, which imo. is nonsense. I bought P/N C2C41899 and it would have fit.

1.) SEAL RINGS: In the “radiator top hose” (JLM21497), which connects to the expansion tank are 2 seal rings. And this is where I had a leak. I checked: Not possible to buy those seals. Only the complete JLM21497 for 105 Pounds plus postage. No thanks! So I did some research and some "engineering" and came to the following conclusion: I can use (ilo. of those 2 black seal, one of them having a very special shape) two slightly "fatter" seals: FKM O-rings CS 3.5mm / OD 29mm. CS is the diameter, FKM is a rubber-like material with impressive properties: It is a fluoroelastomer, which withstands temperatures of up to 260 degree Celsius and is resistant to aggressive fluids. Those are pretty cheap on Aliexpress.

hose JLM21497 at bottom of expansion tank - now with 2 of those green seals (see next picture)

The old seals: black. The replacement I found: green.

2.) WATER PUMP: Again I made the mistake of ordering something before taking it apart. I figured that my old water pump looked pretty poorly and that it could well leak from those 2 hose-flanges at the front, thus I ordered a water pump C2C38862 (or FWP2196 - same thing), When it arrived I looked a bit flabbergasted. I turned it and turned it trying to figure out, if this is the correct pump or not, until I realized: This is the correct pump, but INCOMPLETE! The back-plate (with those 2 hose flanges, which looked so poorly) was not included - just half a pump! They show you in the listings only ever one side of the pump - and it is not obvious, that the other side of the pump is missing. But this is standard! It is just not possible to buy a complete pump. Also, in you-tube videos regarding water pump change, they show you, how to reuse the old back-plate... - which is quite a problem, when exactly that back-plate is rotten to the core. But after long research I found this illusive back-plate for sale from a seller in the US: new, but very old stock. I ordered 8 of them and I polished one part up, and put it on the water-pump, which I got from the UK:

The water-pump... Not the most pretty sight....

That flange for the hose was actually corroded thru at one point: A complete hole thru the material.

The old rotten back-plate, and the new one, which is kind of not purchasable anywhere - I was just lucky.

New water pump with new back-plate assembled already.

3.) "HIDDEN SEALS": Now, when you are looking for coolant leaks, the last thing, which would come to your mind would be to take the engine apart to see, if you can find maybe an unexpected leak at the core of the engine - but this is exactly, what you may have to do:

After removing a whole lot of parts (incl. air-intake and fuel-injection-unit) you get access to that upper hose-flange-bit, which is screwed onto the engine block...

This is the part I am talking about and it has 2 bad gaskets.

And a similar part sits right under this previous part... I guess normally you would be expected to remove the upper left engine block down to the head-gasket, just to be able to remove the second bolt there...!But I just managed to use a standard spanner - painful and time-consuming, but it beats the alternative.

Thus I got the second part off as well, but it was not possible to pull this part out of the engine block, nor could I turn it.

The round thing is a mirror, which I used to see the rotten gasket in there.

I used the mirror and this special tool to pick that gasket (XR85431) out of there and replaced it with a new one. Btw.: see that big oval hole, which is revealed after removing the cover-plate - I replaced that gasket as well: It was very hard to find that P/N. A nice guy from Jagdaim helped me on the phone. The P/N is AJ88279.

And you see the P/Ns of the other 2 gaskets in the picture here.

Looks much better than before: Cleaned with rotary wire brushed on drill, and then spray-pained with clear-coat.

And after very laboriously putting that inaccessible bold of the lower part back in again and all the other part, it looked a whole lot better...

Thus again: Normally you would not expect a potential leak-spot to be hidden under all the other engine components, but that's how they made it. I fixed all that, while I was "in the area" anyway, replacing the magnesium cam-covers, which self-destructed due to galvanic corrosion. So these were my leaky spots and it is all good now.
I hope this helps someone with similar problems.

 

UPDATE:
Although I thought I fixed all the coolant leaks, I had a minor hick-up and consequently fixed another fault...
As mentioned in the thread above, I already bought a new expansion tank - the first thing I bought, but then figured that I don't need it.
But when driving to the garage for a wheel alignment, I lost lot's of coolant. I quickly found the culprit. The coolant expansion tank itself was absolutely tight. I double-checked that by removing it, filling it with water, screwed the lid on, held the outflow-hole closed with my thumb and fed air-pressure into the tank by the little remaining hole - definitely no leakage, BUT:


There is a groove at the expansion tank outflow. Somehow, this was damaged on one side and thus it was no longer wide enough for the clip (of the connecting tube) to latch in. This fault is very hard to spot, but the picture above makes the issue clear. Without that clip latching in the connecting tube was coming off.


Also, initially I inserted as seals into that connecting tube 2 x FKM O-rings CS 3.5mm / OD 29mm, but it turned out that that was not good enough: I added now a 3rd, but different seal ring: 1 x FKM seal rings, ID 22.4mm, CS (cross section) 2.65mm. The 2 inner ones are those with with OD 29mm, and as outer one I used the ID 22.4mm seal. - PS: that "blue cream" is bearing grease. I figured that would help sealing that spot.


I tried to use a little file to fix and extend the damaged groove on the expansion tank - and sooner or later I would have succeeded, but since I had a new tank anyway, I used that instead. On the bottom you see the tube connected with that clip. It sits firm now.

 

Excellent. That connection and hose has troubled me before also. I live in an area that very rarely gets cold enough to freeze but well over 100F for 4 plus months. I use a 60 water to 40 coolant mix because coolant itself is not as good at heat transfer as water and it works great for me. I did the math and the freeze and boil over protection is still more than adaquate. I also use a product that is called water wetter that helps with thermal release

 

Those temperatures you mention are very familiar to me, I just took a look at the world map: California stretches from latitude 42°N down to 32.5°N.
I live in Australia at latitude 31.5°S, thus even closer to the equator, and thus it is here even a little bit warmer. That would be like being in Arizona, just south of California.
I choose to use a coolant ratio of 50:50 (water / coolant concentrate) anyway (although it most certainly does never freezes here), but my logic is that water is corrosive and coolant is a corrosive inhibitor. But maybe I am overthinking this. Anyway, 40% water and 60% coolant concentrate is of cause also fine.

 

Peter, you have too much time. Must be nice.

 

Hi Roberto,
yes, it sure is. I split my time between watching TV, fixing up my Jags and writing about how to fix Jags here on this forum...
And since I cannot fit in this extra bit of information anywhere else, but it fits well in with "too much time":

The rubber of my tibbe key (Fairlane) dissolved and I could not turn the key anymore. Thus I created a new "grip" for it: beer-bottle-lids (from both sides) and lead poured into the centre...

 

Nice, but beer bottle lids? ok, use two of those golf green markers next time. Better yet, DM me your address and I'll send you some for the next time you want to update those bits.

 

I think, "golf green markers" might be plastic-chips... I was pouring hot lead (old wheel balancing weights molten with a heat gun) into the bottle-lid and then glued another lid onto the other side - and sealed the side with black silicon (to seal off the lead).

 

The saga continues: I found another coolant leak...:
The S-Type had not been driven since I fixed it (it will get registered next month).
So it was just standing... and it lost coolant... STILL!
But I found out why and fixed it:


There is a "tell tale sign" which helped tracking the source of the leak: Note the sugar-crust-like white spots on the pulley in the centre of the picture: That is residue from the coolant, which leaked and evaporated.


Next, to find the approximate location of the leak, I looked where all those places with that white crust were and determined, where the leak would have to be to reach all those places. I concluded it had to be one of the two hoses, which I removed in the picture above already.


And there it is: That cut is the leak. Apparently the drivebelt is somehow able to reach that hose and to cut it over time.

Looking at the original Jaguar replacement hose, you can see, that they added there a sharp bent...: That tells me that I am not the only one whos drivebelt "ate" the hose. Looks like a design fault on the OE hose.


So I drove today to our local radiator shop, and brought him that hose-elbow, and he gave me that big one...: It's part No. RH1094 for a Holden Commodore (Holden = Opel = Vauxhall = GM) for AU$20. From that I could cut the elbow and the straight hose on top as well. The OE Jag Elbow would have cost double, and it would take some time time to get here... Also note: The bent in that new part it definitely sharper compared to the OE part, i.e. there will be more clearance towards the drivebelt.


That's the straight part cut, and I still have a bit of hose left for future fixes...


And all the hoses are fine again...

 

Does someone have the exact dimensions i need for the coolant tank oring? I changed it 3 months ago and still leaks, and unfortunately i dont recall the dimensions. I see you have a few of them inside the plug, i only have the one in the factory position
Thank you

 

Hi Darius, I tried to find the old seals in my waste box - but I do not have them anymore.
Anyway, I had TWO original seals! One, which would have been very close in dimensions to the bigger two I am using now (FKM O-rings CS 3.5mm / OD 29mm), and one very oddly shaped seal - it was wedge-shaped. And while I am very good in sourcing parts, I could not find anything like that anywhere - especially not as Jaguar-replacement part. It is very likely that those 2 seal come with the specialized Jaguar replacement hose - very expensive. Which is exactly why I did, what I did, with the 3 seals as described above.

Btw.: I have my S-Type registered on the road now. And It looks like I solved most of the countless coolant leak issues. There seems to be one left though: It looks like - if I drive longer distances (and the coolant gets hot and expands) the coolant seems to leak out of the seal of the lid of the coolant tank. That's an odd one and I will have to keep an eye on this.

 

Thank you so much and im sorry to have had you search for that little seal. I will drain my coolant and get that one out and ill buy one with the same ID but ticker (bigger cross section) and i will lube it and reinstall. i will post dimensions.

 

Hi Darius, I am not sure, if you would be able to get a seal with a bigger OD in there... (same ID with bigger x-section = bigger OD).
So originally there was a normal seal in there (like one of my bigger ones), plus the wedged seal. What I did was basically to "simulate" a wedged seal by using another normal seal and adding a smaller seal to "simulate" the wedged shape.

When you drain your coolant, make sure that your coolant does not get into contact with dirty surfaces (i.e. clean them before) so that you can reuse it. When I did that on my X-type, I got some dirt anyway, but I used a paper kitchen-wipe-tissue in a funnel to filter the dirt out - it just took a while to get the fluid back in again (slow filtering). Maybe a coffee filter would be better, but I did not have one.

Also, as I pointed out in my thread above, make sure that your clamp is positively in the groove.