With my kind of luck you’re probably right: : 
i dont think most of you guys understand Jaguars, especially V12s!
i’m now living in Austin TX ,where just about every day ambient temps are over 100+ F degrees!
talking to some of old mechanics and an ex police of department ,Austin! he managed some of the Parade!
when UK was having a big visit for some BS relation thing,in Austin , they sent 5 vehicles here for the parade, two were like big Damlier’s ,3 were XJ saloons, all V12s , police had to detour 2 of the Dams. to a side street ,boiling over in the middle of the street!
and XJs had to be rerouted to a garage area! before the end of parade, just to save face of Jags!
mechanics in garage said the cooling systems CANNOT keep up with central texas heat in summer going slow!
simply put even today many big cars are borderline overheating, in normal conditions, like Mercedes larger models , have 3(three) large electric fans running when setting in market parking lot waiting for groceries to be brought out! what you think those type people would sit around without A/C on full tilt,LOL.
i believe that Ford/TATA , stopped production of V12s just because the engine cooling system was non effective from the 1st designs!
OK at medium hi way speeds , but some at sustained hi speeds, slowly get hot!
i’m sayin that a coolant that has a very hi temp boil point woulda/coulda helped the problems!
modern engines will tolerate easy 300*F with the oils and metals we have today!
ron
many of the DAYTONA 24 races with Jaguar V12s went DNF, because of overheating,
most late in the race, like 20 /23 hrs in and presto overheat.
sad time in the race espesially when leading!, but remember thats winter and much cooler weather!
ron
pic mine , and I watch a digital readout gage when out running around(mostly car shows),
i avoid slow driving streets and heavy traffic?
it is what it is???
last but not least , a friend of mine,car guy, lives in Saudi, he says yrs ago they didnt buy many Jags because of overheat,120F , finally TATA has made some sales, because they corrected the cooling systems!
NO V12s, sad shame!
ron
I feel better paying extra for the premix. Some reports say distilled water is bad, others that it’s great, having premix just takes that whole adding water out of the equation.
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Deionized water is the bad one: distilled is OK, if needed.
You might be right, or these guys might be right:
If I buy premix, I don’t have to think about it.
The article talks about the semi-precious metal molybdenum. It’s going for about $11/pound. I guess my fillets which run about the same price are then semi-precious?
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From the “No Rosion” posted by John ( it explains a little more and how its ok to use distilled water):
"Q. Should I use distilled water as coolant?
A. Yes. But only in a 50/50 mix. Distilled water should not be used as straight water coolant, because it can cause damage to system metals. The reason has to do with how distilled water is created.
During the distillation process, water is vaporized into its gaseous phase, so all impurities are left behind. These impurities include a number of minerals, including calcium and magnesium, the two components of hardness. The water is then condensed back into its liquid phase, so the resulting liquid is pure water. In fact, some of the purest water on earth. The problem is that distillation strips impurities from water, resulting in water molecules that are electrochemically imbalanced. So distilled water will actually strip electrons from the metals in a cooling system as it attempts to rebalance itself electrochemically. This can result in damage to metals in a cooling system.
Using distilled water in combination with 50% antifreeze effectively cuts the amount of distilled water in half. By compounding with glycol, it will not cause damage to metals in a cooling system. For this reason, it is safe to use distilled water in a 50/50 mix.
Or, scientists may trump a car blog…
Fortunately, with Colorado tap water, I need not worry, either way!
Win-win!
This subject is almost as controversial as the huge horsepower increases from using K&N air filters, or steel tube headers, not to mention the amazing benefits of $25/gallon oil!
Um… I do not think moly is either precious or semi-precious: sleep well.
There is a subject where “distilled” does create a very useful products:tumbler_glass:
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Stirred… not shaken?
Either way is wonderful as long as it’s gin. Now that’ll open up a whole other discussion
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All I know of gin… is Beefeater’s!
It was also the go-to booze for old lacquer painters, because it allegedly countered the bad effects of inhaling lacquer fumes.
If it were really important what kind of water you used, don’t you think the anti-freeze manufacturers would include that information on the bottles? AND on their websites?
Just try to find that information, coming from anyone other than random strangers in countless blogs and forums. If such definitive, true expert information exists, it is buried so deep no normal person will ever see it. That tells me it simply does not matter one tiny bit.
After Googling for almost an hour, I found one no-name anti-freeze manufacturer that recommended de-ionized water, and another that recommended distilled water.
Most, including Prestone, simply said nothing at all.
So, who do you believe? A bunch of unknown internet pundits that claim one is certain death, and the other the solution to all your problems (and there are equal numbers of both)?
Amusingly, the explanations I’ve seen for why each is better (or worse) is EXACTLY the same. De-ionized water, according to some, is better because it has all the ions removed. Distilled water is better according to some, because it does not HAVE any ions to begin with!
I’ve always used tap water, and never had one single problem, even after running for hundreds of thousands of miles. Again, if it really mattered, EVERY bottle of anti-freeze concentrate would make very clear WHAT kind of water to use right on the label.
Change it every few years, use whatever comes out of your tap, and find something worth worrying about.
Regards,
Ray L.
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I do think there are places with hard water, where tap water may not be the best alternative: that said, the secret is the maintenance.
Antifreeze carries an additive package, which allows the use of any decent water. Frankly, were I to live where Af isn’t required…I’d still use it.
When I pulled Tweety’s engine apart (and he NEVER had anything but tap water and regular AF. changes, in his 52 years/200,000 miles) the front cover, behind the water pump, had not one corrosion spot: the steel head gasket, naturally, had corroded some around the water passages, and they themselves needed welding, but only a small amount.
My Rover’s cooling system, which may or may not have had proper maintenance, was nearly pristine, including the large steel water jacket plates, prone to rusting out, which were not corroded in any meaningful way.
What Ray says: this is, again, a solution looking for a problem.
Clean the system.
Power flush it every couple years.
Use the cheapest brand of old green antifreeze.
Use decent water.
Worry about other things…that matter.
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There’s no substitute for a well designed and well maintained cooling system. Most if not all Jaguars are designed with a fully adequate cooling system, which only reason for causing overheating is poor maintenance.
I use Evans for one reason only. The risk of cylinder head hotspots with dropped valve seats as a consequence.
I’m also convinced that Evans saved my engine when the fans stopped working in 20-30 minutes of stop and go city traffic.
The fact that I don’t have to change it, ever, is an added plus I enjoy with Evans in my Ducati as well.
When you live in Southern California (105) today, no humidity,
Evans may be nice to have. I use Evans, upon recommendation of my mechanic and run my air conditioning and the temperature gauge (if accurate) goes to high normal but no higher in stop and go traffic. Seems to work fine.