One more posting I promise!! Aluminium radiators!

thanks for checking back, yes Im going to run a coolcat fan, and radiator.
The cost and hassle of swapping our the fan convinced me to replace both.
Bought the radiator from Welsh.
The thread was enlightening and helpful - thanks all!

Greg,

Don't know if you're still checking this thread but- did you get a satisfactory answer to your Coolkat question? I have a 66 w/ original radiator that always ran hot, and often thought of restricting the bypass, but instead I purchasee a Coolkat and also started running WaterWetter. I no longer have any overheating problems. The Coolkat is simple to install inside the existing shroud and gives a nice non-obvious finished look.

Mike,
Where I live it takes about 5 minutes to get to 70 Deg. C at most. I have owned seven XKEs and here in S. Texas and I want to make sure as much coolant goes through the radiator as possible. I know the thermostat should close off the by pass, but out of the seven XKEs I have owned over the last 30 years, all but the one I modified and the my 68 OTS ran hot. These two do not. In the 68 I have a CoolCat radiator and fans, and my 66 the aforementioned modifications, they both do not overheat now.
Several comments on the Jaglovers forum discuss the changes I made to the 66 XKE at length.
Thanks for the concern. If there is a problem about it, I can always change it back. That is a good thing about just rerouting it.
Charlie

Why would you route the bypass hose to the hot side of the radiator? The whole idea of the bypass is to short circuit the flow until the engine is warm. On S1 4.2's, this is done by routing the bypass to the cool side. Of course, you need to use the correct sleeved thermostat to make that work.

Andy sorry to hear the bad news....where do you live?
The 4.0 is bullet proof in that xjs.
Charlie, the dual switch is perfect, I put it in mine as well when I put in th a/c, it auto goes on once the a/c switch is turned on...
Good luck.
Carlisle was great!
GTJOEY1314

Greg,
I recenlty installed the Ray Livingston aluminum radiator conversion in my 66 E-Type here in Houston, Tx, and installed a Derale 16816 two speed fan with the Derale two speed fan controller. I have a 180 deg.F thermostat in it. I also blocked of the return from the header tank to the radiator on the passenger side and re-routed the thermostat by-pass hose to the hot side(driver) of the radiator. The car stays at 180 deg. F all day long. The reason I installed a two speed fan, is that I plan to install a A/C in the car in the near future.
Charlie
66 XKE 2+2
67 420G
68 XKE OTS

Joseph, I might be offended. we just figured out that I put 634 miles on my xjs last year. (it's been a busy year) our roads are so bad, you are lucky if you can hit
50 mph, never mind 200

Edited on 2013-05-16 19:37:27

Now, now children....I just arrived at Import Carlisle, I drove 235 miles from N.Y. This morning.
Lets all remember there isnt a person on this forum that doesnt hold an AARP card......
Even I have one....Its my wifes but I still have enough gray hair.....tee hee....
Oh back to the radiator.
On my series 2 etype, .......The gauge reads...........NORMAL
With the oversized aluminium rad and racing fan, I run between M and A all day and night with a little fluxuation in the mountains, humidity and all the rest.....
Even with the larger opening, on a series 2 , if the fan didnt work, the engine would blow up.
Everyone is right its all about air flow.....
Yes at 200 mph its moot, but last time I checked, 3/4 of the forum members hasnt turned a key on their jag in 10 years.........haaaaaaaaaaaaaaaa.
ALL BENCH RACERS....
Im just having fun.......
It is a combination of adjusting the fan belt,water pump.anti freeze and mixture, thermostat,rad , fan and yes even air flow, I run a k+n filter nothing else.....
It all helps..........
Will finish my 24 hour/500 mile run in an ETPE tomorrow nite..........
2 weeks, Indy 500, anyone else in?
Enjoy
GTJOEY1314

The point Mike made had nothing to do with race cars.

If you have a fan it is circular and the radiator never is. Therefore the fan sits in a shroud so tat the 'suction' is applied to the full rad area. The flow of air from fronto to back is caused by the difference in air pressure across the core, from high to low. The greater the difference the better the flow. you can create that difference either by using a fan to lower air pressure at the back in stationary or slow traffic, or raising the pressure in front by driving fast and using the 'ram' effect of air entering the bonnet and piling up at pressure in front of the core and being forced through to the lower pressure side at the back.

The ram effect relies on there being no other place for the air in front of the raiator to go except through the core. When new, this is adequate. By now, many cars no longer have the felt or foam radiator or stoneguard seals, or the long alloy plate underneath on the bonnet frame, or the panel in the base of the bonnet mouth and therefore the ram effect is compromised.

More importantly, Mikes point was that if you have the fan running, the pressure differential across the core (and therefore the cooling air flow) is greater than it would be with just the ram effect. Instead of the shroud and the stationary fan blades being an obstruction to passive flow through the core (however slight), they now contribute by causing a lower pressure to add to the speed-induced frontal ram pressure and the total flow goes up.

If the flow at speed was already way more than adequate - as it normally is on race cars - then having a fan or not would be irrelevant. But in a car like the E-type where there was not much cooling reserve once conditions get harsh (or the car is no longer in original spec) the fan could have the effect of increasing marginal flow at speed and it is not unknown for an E to have the fan come on at speed because thermoststic switch is telling it the car need more cooling.

I was going to ignore the response from Michael Frank as I felt that he had his head in the sand. There was nothing in my post that deserved to be ridiculed. I have never driven in high speed racing but in the 70's at Saugas speedway we drove a 57 chevy with a 3.8 XK engine on a half mile oval track. WE USED NO FAN and overheating was never a problem, in fact I believe that none of the entries had a fan. From the time we got the "start your engine" prompt to the flag drop which was about 20 seconds max the temp was at normal, once started I did not even have to look at the temp gauge & this was HOT summer nights. What fun it was. Bottom line any jag, even the sedans, if everything was working as designed IT WORKED.

"My IMSA Olds runs 208 MPH with no fan and it is a 24 Hour of Daytona & 12 Hour of Sebring car. The fan cools the car up to about 30 MPH, above that the frontal air flow is enough."

And this is how Jaguar made their error; 208 MPH is not most people's normal driving mode, nor is a race car a street car. I said the fan is always additive to airflow. I've only tested this to 80mph. I'll have take your word that at 208, this isn't the case.

Even at 30mph, comparing an Olds set up for racing with a stock E-Type is just an unfair comparison. The E-type has a nose opening that has a smaller area than the radiator, thanks in part to the bumper running right across the opening. It has a long, leaky air plenum between the bonnet opening and the radiator, and a stone guard that further obstructs airflow. Some of them have a/c condensers, and airflow through the engine compartment isn't free if the underpanels are in place. An E-Type is always airflow challenged, so don't be surprised if your fan comes on at highway speeds.

I have had the Cool Cat fans on my car for several years now. My recollection is before them with the original 4 blade twin fans my car would run hotter up at highway speeds than it would driving around the neighborhood on a hot day. I always found that odd since most folks seem to have problems at lower speeds. I never have driven it in hot weather in stop and go freeway traffic. Since it is a FHC without a/c it is not much fun anyway for much of a drive when above about 85 outside. Since I put in the Cool Cat fans it allways seems to stay slightly above mid-range no matter the outside temp. or driving speed.

David Barnes
68 E-type FHC

It is NOT an "old wife's tale" that the fan does not matter at speed. It is a true statement proven by the fact that my GT2 E-type SCCA car used no fan at all. I didn't drive it on the street or let it idle. My IMSA Olds runs 208 MPH with no fan and it is a 24 Hour of Daytona & 12 Hour of Sebring car. The fan cools the car up to about 30 MPH, above that the frontal air flow is enough. If your car runs hot at idle & slow speeds but cools down on the road, that would indicate a fan problem. If it runs hot at all speeds it could be radiator, lean fuel mixture, timing problem, thermostat, water pump... any number of problems. Point is you need to know more before just spending money on a radiator. Good luck with the problem.
Cheers Tom

Edited on 2013-05-15 7:37:50

If you keep the stock radiator,and go to any auto store, a high speed fan with zippy ties will be your simpliest answer. Thats if cost and original is a factor. Plus add a HAYDEN adjustable switch and your troubles are ALL over.
Fans go from 30 to 200 hundred dollars, the old school hayden switch with fuse built in is another 30 dollars.....
You can dial in the switch now to kick on at any temp you want..........It has an overide that at 220 it automatically kicks on too.
Many years have past, I like others went the aluminium with the high speed racing fan and it is just wonderful.
I drive mine 10,000 miles per year, in NEW YORK, traffic and it NEVER breaks past 180 ish...in traffic.
Thats a series 2 ....coupe 4.2
Good Luck.
GTJOEY1314

I've studied the S1 fans in great detail, and I can assure you that they are neither efficient nor powerful. Your story is humorous but ridiculous. Here's are the fan curves for the S1 "lawnmower" and the S2 fans:

http://www.coolcatcorp.com/Airflow%20Chamber/OEM.jpg

I believe that the way the S1 fan was designed was to match the airflow at idle from the pump mounted fan on an earlier XK. If your car is idling well at 500 RPM, then the airflow will be good enough. The problems begin when the idle is off for whatever reason: unlike a pump mounted fan, the electric fan runs at a fixed speed, and can't compensate. And Jaguar engineers succumbed to the old wife's tale that the fan doesn't matter at speed. Unfortunately, this isn't the case, and the fan should be powerful enough to augment airflow even when the car is in motion. So the marginal capacity of the S1 fans is a potential problem at all speeds. When everything is perfect, it works just well enough. When things start to deteriorate, that's another story.

E-type radiators would have enough capacity for a small truck if you can keep airflow and water flow up. This is particularly true of the S1 3.8 radiators, which were a superior design to what followed. Airflow should always be suspect#1, due to the long nose, inefficient plenum, bumper location and finally the fan.

Greg, that lawnmower fan, is amazingly efficient, they just have to be driven by a good motor, there are many cars around with the original set up'. There was a story in the UK in the 60's that a 63 OTS without a bonnet, was pushed by a female, with just the fan working, when the fan was turned off the car stopped???

Greg I might add on to what William says. My 68 E-type has the series 2 twin fan set up that my guess is better then the lawn mower fan blade on a 66. It would creep up close to the red scale on 85+ degree day here in Houston. I went thru the system with flush, rebuilt water pump, Water Wetter additive and new stock looking radiator with 7 more tubes in the core than my original but it is not alluminium. That new radiator did not make too much improvement. The real cure for my car was the Cool Cat fans with the modern looking multi-blade fans. It now runs a little above mid-scale on a 90 degree day. The bonus is the fan fuse on my car is much cooler now too. My guess is my origianl fans were tired and drawing too much current even though by site they looked like they were spinning good and flowing a bunch of air

David Barnes
68 E-type FHC

Hi William
Thanks - useful info. Yes, fan is original, which looks kinda like a lawn mower. Always seemed to work, but perhaps thats a better starting point.
Any suggestions for brand?
Is Cool Cat something everyone uses?

Are the fans original? if so they are just as likely to be the problem , As for aluminium, It is very hard to repair, ie, if a stone gets thrown on it, it could make it useless!