XK 140 overheating

I was terrified when the temp gauge pegged above 100C on my 140 in the Smoky Mountains. After much fretting, I used a laser temperature gun and discovered that it was actually 80C. New gauge, new radiator, improved water pump had already been installed so it should not have overheated, and it didn't. Check your actual temperature.

While the alloy radiator may not be a "magic cure" you can't get much better. I noticed a 20 degree C drop over my rodded (but not recored) original. Even if they don't improve cooling signifigantly, it's nearly worth the $1000 just for the looks... matches the XK engine perfectly.

B. Shriver
XK 140 OTS MC-E
http://www.shriverperformance.com

you're right about the alloy rads. It's not the solution often advertised. It will help, it will be better than an old clogged radiator but it's not the miracle cure... When I installed an alloy radiator on my V12 E to replace the crushed stock rad, I really can't say I noticed a difference. Maybe 1 needle width...

Pascal Gademer
72 E-type 2+2
00 XKRCoupe
99 XJR

Daniel has good advice except the alum. rad. They do not help that much. If you have your rad. rebuilt make sure they give you the same vol. that you have. A lot of shops will use modern core that is more efficient but does not have enough vol. Before you launch on this and assuming you have checked as much as you can--check the cam timing. I have several 15-20 XKs that I maintain that run in our heat 100F+ without overheating. The biggest factor in this besides a clean cooling system is CAM TIMING. One tooth off will cause enough heat that you will not recover from traffic. Good luck.
George Camp

The debate on this subject is endless. You have to establish a few golden rules first:

- the water passageways in your engine must be clear of obstruction. Engine blocks that have not been cleaned/boiled since 1956 are likely to have tons of crud impeding flow.
- you must have the correct thermostat for the car.
- as Mike mentioned, the correct antifreeze mix.
- the radiator must be in top shape; preferably freshly recored with a "triple" core.
- a fan may be fitted in front of or behind the radiator (Kenlowe fans are popular), but remember that a fan is useless for cooling an ALREADY HOT engine; learn to anticipate overheating situations and switch on the fan BEFORE things heat up.
- the car must be "in tune"; an out of tune or out of time car will run hot.

Possible remedies:

- aluminum radiator
- pusher fan or puller fan, controlled by in car switch
- overflow recovery system; when fitting an expansion tank (a la Series 2 E-type), the radiator cap is changed to a plain (non pressurized) cap. The expanded water is allowed to flow into a small expansion tank, this tank has a pressurized cap (7 to 10 psi, 4 psi is not enough). As the engine cools down, the water/coolant siphons back into the main radiator/header tank.
- some people swear by XJ6 water pumps, as they do not cavitate above 5000 rpm and supposedly move more water around below that rpm.
- add an oil cooler. Although the XK engine has plenty of oil the addition of an oil cooler can lower coolant temperatures by up to 10 degrees
- add foam on the sides and top of the radiator to seal airflow through the rad.
- finally, and this is an interesting idea: fit an electric inline water pump that is controlled from inside the car. The idea of this is you switch it on when you are stuck in traffic and the little electric pump circulates the water much more efficiently than the engine driven water pump can at low engine speeds. Brilliant!

Most of these ideas come from a series of articles that have appeared in the excellent magazine "XK Gazette", put out by the XK club... http://www.xkclub.com

If you want to get the problem sorted out properly I would suggest getting in contact with Guy Broad in the UK http://www.guybroad.co.uk and have a good chat with him about solutions.

Daniel
2002 X-type
1968 E-type
1958 MkIX
1952 XK120

In front or behind, the fan has about the same effect on high speed airflow. An obstruction is an obstruction. The only disadvantage to mounting in front is that you can't direct airflow through a shroud. As a rule of thumb, a front mounted fan is 20% less effective than a rear mounted, shrouded fan.

What sort of coolant are you using? 50/50 is best, and try throwing in a bottle of Water Wetter.

A radiator recore may be where you're headed.

Mike Frank

Overheating occurs primarily at low speeds or when stuck in traffic. I would really like to put the fan behind the radiator so as to not obstruct the intake at speed, but I can't see any way to do it. Has someone done it this way.

Also, I do need to check the water pump, but I don't think it is the problem.

Another thing I should mention... if it's overheating at speed suspect your waterpump. I had mine rebuilt by Terry's Jaguar, and it made a huge difference.

B. Shriver
XK 140 OTS MC-E
http://www.shriverperformance.com

David,
I was having some trouble with my car overheating as well. I was able to setup an electric fan 14" satisfactorily in a "puller" position, by buying some aluminum 90 degree pieces at lowes (sold by the foot 1"x1"), and then drilled it to fit the fan, and radiator mounts. I have a "rodded" radiator that will fit your car, but it is correct for the early style 140s, so it wouldn't look original in your car. I ended up with a Ron Davis aluminum radiator from Classic Jaguar... if nothing else it sure complements the aluminum on the engine.

B. Shriver
XK 140 OTS MC-E
http://www.shriverperformance.com

Beautiful car !

Does it only overheat at slow speed ? what about when you start moving at speed ? if it only overheat at low speed then your issue is with moving air thru the radiator... Many people have installed pusher fans in front of teh rad, it doesn't really block much air.

another possibility if indeed you run ok at highway speed is that your radiator needs to be re cored or changed. I'd try the fan first.

Pascal Gademer
72 E-type 2+2
00 XKRCoupe
99 XJR