That is not good at all, it needs to be changed ASAP. If you drive it ( and I'm not sure that I would if you have another car) keep an eagle eye on the coolant levels. If it was me, I'd take the valve out of the hoses and put in hose mender to join the two hoses together and bypass the valve until you can get it replaced.

As it warms up and with increasing engine speed you can lose a lot of coolant quickly, and overheating is the enemy of a V12.

 

Indeed. I keep an eagle eye on coolant levels normally, but several now of course. Plus I am often checking the temp gauge as I drive (and it's fine). At least the leak stops when the aircon's not in use. So it's reasonably safe to drive without the aircon on, but I really would prefer to be able to use it. But I think I will use my other car more.

 

Do not use it until the valve and hoses are changed.

 

Noted. I will have to drive back home, however....

 

Grant - I've tracked down various vendors and compared prices and seen if they have other things I need, but I do have one question if I may.
You said I needed to replace the hoses. Thinking back on it, I actually replaced the entire cooling hose system with a set from David Manners in July 2016. Set HK029 according to my receipt, which would appear to be the same as this kit here. A 14-piece kit, which I assume contains the same as this one from XKs Unlimited. That kit contains the three hoses in question, which presumably means my three hoses are all only four years old.

So, the question is, is your recommendation/order to replace the hoses based on the assumption that they're the originals and nearly 30 years old, or because the leaking coolant would have ruined them?

 

OK, if the mechanic actually changed them, then NO.

Sadly, your snaps of that tap leaking make the hoses look very sad, hence my original suggestion.

Those 3 are often in the too hard basket, and I have even seen "repairers" use ArmorAll on them so the owner thinks they be new, MONGRELS.

If you are 100% they be the new ones from that kit, do the tap only. Hell of a call from here.

 

I would be astounded if my place was quite that bad. I would imagine they are a little more concerned about their reputation than some el cheapo place. At least I hope so.
The video of the drips was taken on my tablet, so the image is somewhat below potato quality, but I'll take another look at the hoses again and see how new they look under any grime. Do the hoses also look bad in the original post? There is one hose that looks pretty gunky. I'll see if that cleans off. I'm not actually sure what hose it is. It's below the heater valve, anyway. I'll check in the morning. So long as it's not raining...,

 

Good idea. Just look at them, give them a squeeze, usually old gunky hoes are hard and crackle a bit when attempting a squeeze.

That lower hose would be the emissions air pump, no coolant, well there better not be, inside it.

 

I'll double-check those in the morning, but so far none of my hoses has ever proved to be hard or crackle-like. A while back the return fuel hose wasn't as flexible as the other hoses, and it got replaced smartly.
So I guess that lower hose runs up to the Y-shaped bit for the air injection...? I'll see tomorrow, I guess.

 

If your hoses are only a few years old they are fine. If they were the original ones then it's a "you might as well" sort of job while you're there and the coolant is partially drained. Not changing the hose will make the job quicker and spill less coolant.

 

Well, I checked the hoses around the heater valve, and they're all nice and soft and flexible. I think they can stay where they are for the time being. I also experimented with removing the balance pipe, and discovered two things.
1. It's a lot easier to remove from the manifold end of the hose.
2. I need a new starboard (RH) connector hose. Not only is it much, much harder than the port (LH) one (which I can squeeze), there is a split in it. This, I assume, is not ideal.... (I am trying to track down the part number in JCP, but boy, they are hiding the balance pipe well....)



The other hose isn't trying to look like it's wearing a Victorian corset.


And for reference, here's the clearest shot I could get of the water valve hoses, showing them on either side. They seem fine. Soft, pliable. Good for a few more years yet. (I note that the valve itself says "Assembled in Mexico"...)


(Ah, here we go at last: Balance Pipe Hose EAC2654)

 

Correct, it's not good. The reason is there are two ways to determine the amount of air coming into the engine: The current way cars do it is with a mass airflow meter, to determine how much air comes in and thus how much fuel to add to achieve the target air-fuel ratio. Not that's mass of air, not volume.

Before mass air flow meters were invented, the way to do it was by calculation. The ECU needs to know the temperature, the vacuum level in the engine, atmospheric pressure, and the engines volumetric effeciency across the entire rev and load ranges, and then it is possible calculate the mass of air going to the engine. The vacuum level corresponds to the engines load, so lower vacuum levels equal higher load, and more fuel is added. The split lets extra air in and reduces the vacuum level, so it will run rich compared to what you want, and probably have a high idle speed too, since you now have uncontrolled air coming into the engine.

It's been a long time, but I think I used part of a radiator hose from a early 90's Mazda as replacement pieces for those hoses. I just wandered the junkyard until I found a radiator hose the right diameter and approximate bend I needed then cut it out.

 

Thanks for that. I think most of the split is over the metal (the top photo shows it partially eased off), but I'm sure some gets in. I haven't noticed overly high idles, though she may be running a bit rich. Fuel economy seems to be not great (less great than usual), but that may be partially due to too much stop-start in town and too much hooning in the hills and not enough cruising. A Mazda rad hose would be a lot easier to get hold of, that's for sure.

 

The catalogue I use ( rockauto.com) shows a 1990 Mazda 323 having a hose that is 30mm ID. Is that close to the diameter of the balance pipe? A couple of mm either way can usually be compensated for.

 

SDSD
I changed mine for top notch silicone hoses from Viper Performance. On my car the pipe needed I inch diameter (25mm) hose. They will not perish or fail under heat.
https://www.viperperformance.co.uk/s...ight-hose.html
Cheap silicone hose are not worth it.
The effect of a hose split (if it actually leaks air into the manifold) will be the ECU gets an incorrect vac signal and the tickover will be fast, if not out of control if the leak is big enough.

 

Agree, that hose is a throw away item.

Remember, apart from idle issues etc etc, if the ECU "sees" less vac = more fuel, and more vac = less fuel, AND, that is very a simplistic explanation of the operation.

Vac leaks, any size = no good.

 

I was certainly not going to get cheap silicone hoses, don't worry. Cheap parts cost the same to ship as expensive parts. The price of those Viper Performance ones is a bit higher than the actual Jag parts, and I don't need a whole metre of hose. When you add in postage, I would prefer to buy from a Jaguar specialist that has all the parts I want so I can bundle and save on shipping. Jaguar Classic Parts has everything, for example, though their heater valve is a little more pricey than others. JagDaim in Australia, Welsh Enterprises and JagBits in the US (though JagBits is always expensive). I have quite a list of things I want, you see:
1. Water heater valve
2. Fuel cap (the rubber on mine is too hard and doesn't appear to be sealing properly anymore)
3. Air filters (haven't been changed in three years)
4. Radius arm bushes (going to put up a post about that soon actually--to confirm if they're as bad as I think they are)
5. Balance pipe hose
6. Maybe some other stuff

 

SUGGESTION

Get both balance pipe hoses.
Get the 90deg elbow hose on the top of the AAV, they split for no reason. MONGREL to fit, but there is NO alternative. EAC2655 just for you mate.

 

This one here, then? According to JagBits, it goes from the AAV air valve to the left intake manifold. I'll take a look when I can (might be working late tonight).


Part No. 3 in this image.

 

On checking, I'm not so sure the AAV hose needs replacing. It feels supple and new, no sign of issues, and there's "08/17" stamped on it, which MIGHT be the date. And, come to think of it, it would have had to be removed to take off the manifold, which has been done at least twice in the last couple of years. Here's a photo I took just now:


AAV and hose. Hose nice and pliant. You can also see an extra earth leading from the manifold to the bulkhead that was added last year.