I have a 1995 Jaguar XJS V12 6.0. Coping with Texas summer heat has proven to be a real challenge with over 100 deg F being the norm. The V12 runs very hot so it’s time to consider a cooling upgrade.
There appears to be 3 options with various price points.
Option A. At $US1094, the wizzardcooling provides both a quality radiator and twin electric fans
[https://wizardcooling.com/1976-1996-jaguar-xjs-v12-aluminum-radiator-with-medium-profile-fan-bracket/]
Option B At $US719, V12 offer an aluminum radiator
http://v12performance.com/mm5/merchant.mvc?Screen=PROD&Store_Code=F&Product_Code=CCALXJSV12&Category_Code=CC
Dual fans can be at for an additional $US499
http://v12performance.com/mm5/merchant.mvc?Screen=PROD&Store_Code=F&Product_Code=CC2fan&Category_Code=CC
Option C
At $US350 there is another option (there are variations of this, all around the same price point
https://chrracing.com/products/aluminum-radiator-fit-jaguar-xjs-v12-xj12-a-t-1976-1996-1986-62mm?variant=31981360808074&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=Cj0KCQjwg8n5BRCdARIsALxKb956QoAuJ5lp2lRtX5haa02PRjtAeZajl3Q1qUh67ZblmWyZSbxBb3oaAmFyEALw_wcB
Separately, there are dual fans bolt-ons that would add about $US150 to this to obtain fan-assist
So, fellow members…comments, experiences with any of these options, please
Thanks
Chris
Step 1 is always to pull your radiator and clean the fins, if you haven’t already done so. When clean, the stock radiator should be more than enough. It’s only recommended to look into the aftermarket aluminum rads if there’s something wrong with yours.
Fans are another story. The stock fan is also adequate if the fan clutch is working fine and the idle is set high enough. Unfortunately it’s difficult to confirm if the fan clutch is working fine. I usually recommend simply replacing it with an electric fan setup.
Problem there is that a good many aftermarket electric fans do a better job of moving money out of your wallet than moving air. Some of them suck, unfortunately not literally, and their CFM specs are misleading. I chose to use a 16" fan from a Chevy in a junkyard because those are made to truly move air. It also cost me something like $15, complete with a warranty that if it doesn’t work when I get it home I can bring it right back and swap it for another one.
I would first recommend pulling that radiator place, and taking it to a shop to be recored. Will probably cost you less than $200 and you’ll keep your solid built radiator, which will probably work as well as it did when the car rolled off the Coventry line. Can’t beat that price, and you won’t have to worry about aftermarket connections being exact.
For the fans, I would suggest doing what Kirby did. I believe there are MANY posts you can read on this forum that will detail what fans will successfully work on your car.
Basically, don’t reinvent the wheel. Refurbish the existing radiator and copy someone else’s fan choice so you know what you get will indeed be an improvement.
I would also reconsider v12performance.com. I could be mixing this store up, but the experiences as reported on this forum has been less than positive.
The fan clutch is not costly ($40?) and easy enough to replace. I did mine w/o even checking old one, but i was also replacing yellow fan.
My car runs very cool, but the summer norm is 75F, and heat waves are 90F. The reward we get for the 9 months of rain!
Gentlemen…many thanks for your replies and advice. I guess that the first step will be to remove the radiator and inspect the core. At the same time research what electric fans are recommended. I’d like to replace both existing fans with a dual set-up so will also plumb the Forum for ideas on that I enjoyed Kirbert’s reference to moving cash of of one’s pocket as opposed to CFM!
Here in austin with the traffic and summer heat (4 weeks of rain if we’tr lucky!), I’m going to need more than a fan upgrade I think?
As I was about to do business with V12 Performance, I noted Veekay’s comment. Please feel free to PM me if you would like to elaborate
Try to flush out or dissolve as much of the rusty debris that sits inside the block while you have things apart.
kind regards
Marek
Nope, fan upgrade should do it.
Just curious, why is an electric fan better than a clutch fan? Doesn’t that big clutch fan put out a lot of wind? I know mine does. I thought the main reason to switch was gain a bit of HP on the engine.
Thanks for the reminder…will do!
I sure hope so so as to extend pleasure of ownership…! 
Chris,
Being unlucky owner of anything with V12 in the title - I would start from the basics which somehow are not even mentioned here.
First - I would remove bonnet’s insulation. This is fully reversible, just buy spare stainless starlock washers (as the one installed are probably rusty anyway and will be destroyed on disassembly) and keep your insulation mat under the bed - just in case if you’ll need it. It won’t make your engine noise worst - but even better - it’s v12 not German Trabant 601… With this - you’re gaining 2 square metres of heat sink (self-explanatory). Every jaguar v12 owner apart from those in arctic regions should do it.
Second - replace the foam crap seals around the radiator with something more modern. Guessing yours were probably turned into sand on the side of the road 5-10 years ago. Those are necessary to force the air through the radiator cores and stop air moving around it. You have to remove top panel and fan induction plate to do this. Top of the radiator is the most important part.
Third - addition of that nice v12 engine top cover i. 6.0 version was probably Jaguar’s commercial decision - to make something old (i haven’t said obsolete, I haven’t!) look more modern. This actually makes things even worse in terms of heat build-up between the V-s. In Coventry, UK - most of the rabbit cages are covered with these…
Fourth - remove the bonnet seal, cut off two parts 6-7 inches long from it and install these strips on each side, in the area where the rubber stops are installed (adjust those too to make bonnet shut slightly higher). That will induce airflow in the upper part of the engine bay. Visually - no difference.
Fifth - install thermostats with lower opening temperature you can go as low as possible to find on the market.
Alternatively but not recommended:
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You can do nothing and run with your heating fully on same as most of V12 owners in UK, but here the weather is… slightly different.
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Drill viscotic clutch through in two-three places on the same PCD and lock it with use of m5 bolts and nuts. While slightly dangerous - the heat gauge will drop in seconds while you’ll rev the engine (with visible deflection of the radiator…). If you’re lucky - fan will last the whole season. The special effects - hoover-blower below the car and scared pedestrians.
As Kirbert mentioned - most of electric fans have geometry designed for static use (while stuck in the traffic f.eg.) not for doing 30-60mph… Good to be coupled with your moonshine distiller, not good for the car. It will actually suppress the air flow over the certain road speed…
If not for the difficulty of ensuring that the fan clutch is working right, they’d be pretty much a wash. The belt-driven fan lacks flow at idle, but if the idle speed is high enough it’s not a big issue.
Meaning they look pretty sitting on the store shelf.
Removing the clutch fan means you can also ditch that belt and the idler - not a small amount of weight to be lugging around. You swap the failure modes of the manual fan (broken/lose belt, clutch going bad, cracked blades) for electrical ones (fuse, wiring connectors, temperature sensor). I’m happier debugging electrical issues than the mechanical ones.
If you visit my website, you will find a link to send me an e-mail. I would be glad to share some information re the owner of V12perf****** SD Faircloth www.jaguarfuelinjectorservice.com
My Hayden clutch, upgraded black fan and re-cored radiator do a very good job in keeping my engine cool even at 40°C here in Southern France. I’not stuck in trafic much though…
My next upgrade would be replacing the Auxiliary fan with something more adequate to help with cooling at idle.
Hey thanks for your comprehensive reply…most interesting, I’d already removed the plastic cover from the top of the engine (due to loss of the “special” screws. Looks like a real engine now. The car is young and has been well looked after so the bonnet insulation is in fine shape as are the carious seals and rubbers.
As the real issue is Slooow traffic driving in above 100-107 degree F heat here in the summer months. I only drive on highways in the remaining 6 months of the Texas year.
To reflect this, my current plan is to
- remove radiator and remove any accumulated debris…if condition warrants, replace with aluminum radiator.
- ditch the viscous clutch, idler pulley and belt and the existing electric AC fan
- install dual electric fans (the best money can but) and add the control to either come on automatically at a preset temperature or with a manual override. This will require considerable electrical ingenuity I assume?
- install low temp opening thermostats as you suggested. Does anyone have the correct temps and and numbers?
BTW…thanks again to all Members who have added their comments. Much appreciated
Chris.
Not really. The cheap and easy way is to simply use the switch that controlled the original small electric fan, possibly using a relay (or two) to handle the load. To go one better, some of us choose to control only one fan with the original switch and add another control system for the other fan, thereby achieving some redundancy as well as essentially having two stages of fan operation, one running or both running. Electric fan control switches are readily available, although note that most of them sense air temperature rather than coolant temperature. It’s better to sense coolant temperature (radiator exit), but air temperature will work especially if you’re sensing the air that just came through the rad.
Some have opted to purchase the kit for installing an engine heater in the lower radiator hose – replaces the one long hose with two short hoses and a section of pipe with a fitting for a block heater – and then installed a coolant temp switch in place of the block heater. And of course you could just fab something like that rather than trying to find the Jaguar block heater kit.
Don’t go colder than 180F. You can end up with the EFI system running full-time in the cold start mode.
And how do you propose to determine that?