So I go to check my engine room (it's what I do instead of going to church to experience being in the presence of Mystery and Power...) and discovered a pool of dark green coolant pooled in the vee at the back, on that waffle bit. I manage to clean some of it off, then today I go for a short drive (commute to the uni) with the aircon on full blast, and find that the pool has been replenished. It evaporates off, then I drive home in the evening with no aircon on, and no apparent new coolant pooling.

My first thoughts turn towards the water heater valve, and there are definitely signs of it leaking. Though there doesn't seem as much leakage as one might expect given the pool size, and I can't quite trace the route. Though the water heater valve is the only thing I can think of in that area that would dribble coolant onto the vee....

Also, on checking the levels, I found a rather remarkable amount of crud around the neck of the reserve tank. I hope it's just that leak prevention stuff the garage keeps putting in (I'll be more forceful next time), as it's a fairly consistent sludge. But then again, what do I know? Hence the appeal to the great minds of the forum for their wisdom and expertise....

Some photos for your enjoyment and edification (the second more than the first, perhaps):

Hmm. Don't want to see this in the pipe....


This is why you wear gloves to work on your car, boys and girls....


Poolant o' coolant


Hmm. This looks suspicious....


Some stains here as well:


Looks like quite a bit of coolant has piled here over the... weeks?


Looks like a rusty rubber hose. Presumably it's not both....


Anyway, is it time for a new water heater valve, or can I get away with just tightening some screws? If so, which ones? (It's time for a new water heater valve, isn't it?) Any other parts I should replace in that case?
Access in the facelifts doesn't look too bad--removing the crossover pipe will go a long way to getting at it.

Thanking you all in advance for any advice....

 

Yep,

Heater valve (tap to us) is toast.

Whenever I do them, I always replace the 3 related heater hoses. PITA on Pre cars, no idea on yours, but they are the ones that usually let go and destroy an engine.

Those taps will pump out serious amounts of fluid once the system pressurises.

That coffee stuff is a SERIOUS NO NO, and the garage needs a BIG stick up the backside, NO joking.

I would be flushing the whole system while doing that tap, heater core included, and try and purge as much of it as possible.

 

Agree with grant, the valve needs replacement. Mine had a very small pinhole on one of the heater hoses, couldn't see it until the car was hot and system pressurized and then there was tiny fountain of coolant, just a mist.

That's is a nasty accumulation of crud inside the radiator neck, just think how that could clog the tubes inside. A sound radiator doesn't need any stop leak gunk, it's a bandaid fix at best until a proper repair can be made. Jaguar's recommendation to use that crap is one of their mis-steps.

 

A generic GM type valve works here, you don't need the heavy metal unit from Jaguar with it's absurd cost.

That cooling system needs a professional flush, you may get away with doing it yourself I always had luck (if you can call it that) with liquimoly rad flush followed by MetalRescue added to the system

The flush is just that, metal rescue is a ph neutral rust converter that will turn rust into a fine suspended black silt. Ideally you'd have a spin on coolant filter for that. My filter caught quite alot of gunk and silt over the years.

 

Thanks for your comments and suggestions, everyone. Very helpful.

The valve appears readily available, and not too expensive (Moss Motors has one for $44.99, for example). I'm a little confused about the three hoses you mention, Grant. Jaguar Classic Parts only has a diagram for the 4.0 litre, and while the valve (tap) itself is clearly identical, the hoses may not be. Especially as Moss Motors shows slightly different hoses.



Jaguar Classic Parts diagram for the 4-litre.

Moss Motor's diagram.

Grant's statement that there are three hoses makes me suspect JCP's diagram is the right one. Unless Moss simply isn't showing the hose that bypasses the valve.
These hoses are:
#1 C45016
#2 C45016
#3 CAC9800 (expensive!!)

If I read the diagram right, Hoses 1 and 2 plug into each end of the valve, but Hose 3 goes right past it. They're all available from Jaguar Landrover Classic, though the valve isn't, so if I find a place which has all four I might order there (also need a new petrol cap, new air filters, and a few other minor things--I hope global shipping isn't too disrupted these days...).
I'll take another look at the car and see if I can spot these hoses, and what access would be like. In general, the engine bay in the facelifts is a lot more open than the older cars, so I might be in luck....



I definitely want to get the system back-flushed after seeing that muck. I was figuring it was coming up to time to replace all fluids (save engine oil, which has just been replaced) - coolant, power steering, transmission - which I would get done at the bi-annual inspection coming up in July. Perhaps the situation is a little more urgent. Then again, the parts might not arrive before July anyway....

Is that gunge in the coolant likely to be leak prevention stuff then? My suggestion was only a suggestion. I've certainly considered filters, but there seem to be arguments on both sides. Well, we'll see what sort of crud there is after a good back-flush....

 

The Y shaped pipe you identify in the photo is for air injection. There is a small pump on the right side of the engine that adds extra air into the combustion chamber to start the catalysts going. On my 6.0 it's clutched like an AC compressor and only runs for about 45s after startup. The pieces at the top and bottom of your red rectangle are check valves.

The diagram for the heater valve is under the expansion tank section. Hoses are C43999, CCC6343, and CCC6339.

 

Thanks muchly, Jagboi. Under the expansion tank heading? I suppose they carry coolant, so maybe.... But finding parts on JCP can be really hard. Why would the same unit be under "Cooling System" for the V12 and "Air Conditioning" for the I6? Argh!

Thanks for the info about what the Y-shaped thing is. So air is pumped into there by the AAV (?) when the engine starts, is split by the Y into the two channels, and squirted into the injector area? So a cat-delete car wouldn't need that guff. My car, however, almost certainly needs the cats to be road-legal.

 

Not to distract from the original topic but do you have to get the car inspected annually like in the UK or whatever? If you can ensure there is an exemption or no need - then I'd?suggest ripping out or gutting CATs and air injection its just less crap in the way.

The honeycomb inside the cats gets so clogged its a fire hazard even without a loss of ignition on one bank which usually causes most v12 fires.

As for parts shipping my snail mail parcel to you took what? 10 days on the cheap option? If you order direct from jaguarclassicparts they will air drop the part in record time. I once had a set of coolant caps sent from UK to my door in 14 hours/7500km.

 

It's known in Japanese as "shaken" (sha=car ken=inspection, not what Bond has his martinis like), is every two years, and is an expensive undertaking because of all the taxes and stuff. In addition to the inspection fee itself, which varies from place to place (my place charged me about US$300, on the upper end), there's an approx. US$500 weight tax and US$250 compulsory third-party insurance (which is the bare minimum, which isn't enough, so if you don't take out your own insurance you're insane), a US$90 agency fee (for the garage to go to the actual government office to do the paperwork), and a US$90 "inspection fee using inspection equipment" whatever that means. (In addition, there's a annual US1,000 vehicle tax based on the engine displacement--which is why mine is so expensive.)
All this assumes no actual work needs to be done to get the car to pass. That's extra.
You can take your car directly to the government depot and save the inspection and agency fees, though you still have to pay the taxes and insurance. I did that when I owned a motorbike (you just fill in the required inspection form yourself), and they test it for various things there, but for my cars I've usually needed some work done anyway.

Doing some research, strictly speaking a cat is not legally mandated to pass the inspection, but it has to clear the emissions requirements, cat or no cat. Whether an ancient V12 can do that without cats is... not likely, I'd say. There is a provision for older cars, but they have be pre-1973.

 

Emissions at idle? With o2 sensors and an idle adjustment widget on the ecu to turn it, you could probably get that real lean for the day of the test. Evading emissions requirements has been elevated to an art in places like California lol.

 

I agree, the JCP navigation isn't the best. Just takes time to learn it's quirks, but even then I do a fair bit of hunting to find what I need.

To remove the heater valve, the balance pipe comes undone and can be moved to the side ( the hose that goes to the ECU in the boot can be left on) but all the air injection piping can stay where it is, there is enough room to work around it. Same with the heater core hoses, there is just enough space to get a ratchet in loosen the hose clamps and change the hose. Absolutely no extra space, but Jaguar left enough that is it is possible to change them without too much pain.

For the air injection, it takes the air from behind the right side air cleaner. There should be a rubber grommet and a pipe on the side of the air cleaner housing toward the engine and that goes down to the air pump. The air is then them pumped back and up to the Y pipe and splits to the pair of check valves and to each bank's intake. If you ever need check valves they are the same as used on millions of GM cars and much cheaper to buy as a GM application. I forget what it is now, but I matched the thread size and hose nipple size, as there are two main sizes that GM used.

Not all cars with catalysts have air injection. As an example, Canadian cars had catalysts since 1973, but the HE didn't get an air pump until 1988. Prior to that there was a dummy pulley in place of the air pump. On the Series III XJ6, US market cars had catalyst and air injection, Canadian cars had catalysts and no air injection.

 

Very informative post, thanks.
Hmm. That actually sounds like something I could do myself. I should experiment by seeing if I can actually get the balance pipe off, first.
1. Remove balance pipe.
2. Unscrew and remove old valve. Actually, I suspect coolant is likely to gush out at this point. Enough would need to be removed to let me unplug the hoses without it all pouring out.
3. Unscrew worm drives on clips, pull off hoses from bulkhead connection.
4. Same at other end, wherever that might be. Will need to trace them. I know where one goes at least. It was leaking at the engine end a couple of years back. When it got fixed, the garage applied some sealant around the join to be extra safe. Shouldn't be too hard to remove.
5. Reverse everything.
Removing the coolant could be an issue. Suck it out with a hose? A large syringe? And I want to get the system flushed, anyway.

Ah, I think I know the grommet and pipe of which you speak.


One of these.

Useful note about the check valves. Pity Jag didn't use Toyota parts over GM parts--much easier to access (rather, shipping would be a lot less).

 

It's not too hard to do. The heater valve is actually near the highest point of the engine, so you won't lose a lot of coolant. Some, but it won't be a flood. From memory, the valve is attached to the bracket by 5/16" nuts. A 1/4" drive ratchet and socket should do the trick. I find a socket is actually a much easier way to unscrew the hose clamps than a screwdriver. Depending on the age, they will generally be either 1/4" or 6mm hex.

Rubber hoses tend to adhere quite well to the metal nipples they go over, so the trick to getting them off is to use a small pick or screwdriver and work it between the hose and metal.. Work all the way around if you can to break the bond. Then when you want to remove the hose, twist, rather than pull. Twisting back and forth will loosen the hose much more effectively than a straight pull.

For the balance pipe, if the hoses are original they might simply disintegrate when you try and take them off. Mine were baked hard from heat. I found a portion of a radiator hose that was the right diameter and cut out a section that had the right bend. I can't remember what car it was from, but I didn't buy the Jaguar hoses.

If you were to remove the coolant, the easiest way is to remove the lower radiator hose. It won't get all the coolant, but a lot. You'll probably end up getting a bath of coolant, or at the very least lots running down your arm. To borrow a phrase from a friend of mine who works for a railway as a heavy duty mechanic: "It's like repairing locomotives while they are underway. Technically interesting, but not much fun". It's a messy job, one I particularly dislike.

Yes, that rubber elbow is the air supply to the pump.

 

So plenty of rags around to catch any spillage, then. Some bungs to shove in the hoses as soon as I detach them, perhaps. Thanks for the tips about removing the hoses.
As a newer car (early facelift), I wonder if the nuts are all metric. I don't have any imperial tools. Might be able to get some, of course--and use them on other things. I think Costco has a set.
I think my balance pipe hoses should be fine--they're still pliable, at any rate. I regularly check the main hoses--just give them a squeeze or push, preferably when the engine's a bit warm.
At any rate, I shall experiment with the balance pipe, but not today--it's raining fairly heavily.
Thanks very much for the write-up. Much appreciated.

 

Generally speaking, the car will be a mix of metric and imperial fasteners. At least my 1994 is. I don't know why I'm surprised there is a Costco in Japan, but I didn't know that. Globalization at work.

If I was just replacing the valve, I just bend the ends of the hose up and then no coolant runs out. Since you intend to replace the hoses, you will spill some. Good news on the balance pipe hoses, they should be removable with out damage then.

 

Costco's a relative newcomer to Japan, and especially my corner of it--opened locally in 2018. No Walmart, thankfully.

I've been told I should replace the hoses by Grant, so replace the hoses I shall (I have no idea of their condition). They're not that expensive, after all. I don't have to get that v. expensive 4.0-litre one at least....

 

I wouldn't cheap out and instead buy the genuine hoses. The only hose failure I have had was the left side heater hose that goes down toward the expansion tank. Otherwise, I have found the original hoses were very high quality and the replacement ones are noticeably shorter lived and generally inferior quality.

Does Costco sell tools there? A moderately sized socket set would probably come in very useful if you intend to do much work on the car yourself. I can't recall seeing a socket set at Costco in Canada, but I've not really looked either. My small set that I take to the junkyard goes from 3mm-22mm and 5/32" to 7/8" in both 1/4" and 3/8" drive with corresponding ratchets and extensions. It will cover a lot of what you'd do on the car that is routine maintenance. Add in some regular or gear wrenches from 5/16" to 9/16" and a 10mm and 13mm and you'd be well equipped to tackle many of the regular jobs on the car.

 

I've seen a lot of URO hoses (and other parts) for sale, and don't worry, I wouldn't touch those. I try to get genuine OEM whenever possible, unless the word is that the replacement is actually better for various reasons. I don't ever get the cheapest part hoping it'll work. Because the part is the least of the costs involved--shipping and labour mean that there's no sense buying a part that is more likely to fail.

Costco does have a few tool sets here, and I'm pretty sure one is imperial (assuming they still have it). Or I can just order from the US. Thanks for the mention of the most useful sizes. I can see if Costco has those sizes easily enough.

 

Something like this would do the trick. https://www.canadiantire.ca/en/pdp/m...9215p.html#srp You wouldn't need the screwdriver bits or Torx, but it gives you an idea what is in a set.

For wrenches, I love the flex head type. It ratchets on the ring end, plug moves, so can fit in many places. An example:
I sometimes think between 7/16, 1/2, 9/16", 10mm and 13mm 80% of the car could be disassembled.

 

Ah, I've seen those flex-head wrenches at the local DIY stores, and thought they were pretty cool. Just haven't been sure what sizes to look for. I have a much better idea now, thanks. A 10 and 13 mm will be easy. The inch ones might be harder to track down. Then again, would converting say 9/16" into mm and getting the nearest work? How big is 9/16"? Okay, 14.287 mm. (Useful chart.) So how important is that 0.3 mm (rounded up) in getting off a nut?