I have the usual 120 problem of overheating in traffic. I would welcome
comments / help from those of you who have dealt with the problem. I have
had the radiator dismantled and cleaned and the original water pump
reconditioned. Comments so far:
Electric fan: The most common solution. Recommended to just buy one at
the local parts store and set it up in front of the radiator, 15 inch or 16
inch available, can be installed without drilling anything, making up
appropriate brackets and using the pipe between the guards. Can however be
a big drain on the electrical system, but will only be used during the day
i.e. not when headlights are on, and can be manually controlled. I note
that CAC (UK) have 2 types of Kenlowes I think - one for standard
electricals, the other for neg earth - presumably with the greater power of
the alternator. The answer might be as simple as that?
Electric water pump: Installed in the radiator hose somewhere, I heard
they work well - but have not seen details of these for a while. Used as an
auxilliary fan. Looking on the net I found for $350: EMP Stewart
Components Electric Water Pump. Also: “Inline Booster Pump - Stewart’s
inline booster pump is intended for vehicles that experience overheating
problems in low RPM situations. Since mechanical water pump speed is
directly linked to engine speed, overheating becomes a major problem in
situations such as parades, cruises, and stop-and-go traffic. The inline
booster pump solves this problem by working in conjunction with the
mechanical pump to create constant added flow to the engine block; the pump
has been proven to increase flow by more than 300% at idle! These pumps are
currently being used by NHRA Pro Stock Champion Warren Johnson and Kurt
Johnson by Dart Industries, and Jim Yates - as well as road racing American
Lemans and SCCA World Challenge. Code: E558A Price:$404.70”.
Variable pitch fan: Offered by XKs Unlimited at a huge price - over
US$500 I think. I emailed them for info about the specifications and tests
as to performance - and never got a reply. So it is not possible to count
on that as a solution - unless one of you guys knows better?
Alloy radiator: One owner said it made no difference. Another workshop
could not explain to me why it would help. Does not seem to be a solution,
I guess you use one to save weight and because I was told that making one
was no dearer than making a steel / copper / whatever one, from scratch.
Hi John, I don’t have answers for you ,just more questions.
Electric fan–would that be better placed on the engine side of the
radiator.I know that means controlling thermostats and probably upgrade to a
alternator. Does a fan placed on the engine side increase air flow? Why do
most modern cars have it in this configeration? The normal engine fan of
course be removed.
2.Air flow through and around the radiator. I have sealed all areas where
air could bypass the core ,as in over the top ,around the sides and down
and under.
Oil radiator. With the amount of oil the XK motor has, would a oil
radiator be a worthwhile suggestion.
I haven’t the answers ,just the questions, perhaps someone on the list has
already been there and done that??
I have the usual 120 problem of overheating in traffic. I would welcome
comments / help from those of you who have dealt with the problem. I have
had the radiator dismantled and cleaned and the original water pump
reconditioned. Comments so far:
Electric fan: The most common solution. Recommended to just buy one at
the local parts store and set it up in front of the radiator, 15 inch or 16
inch available, can be installed without drilling anything, making up
appropriate brackets and using the pipe between the guards. Can however be
a big drain on the electrical system, but will only be used during the day
i.e. not when headlights are on, and can be manually controlled. I note
that CAC (UK) have 2 types of Kenlowes I think - one for standard
electricals, the other for neg earth - presumably with the greater power of
the alternator. The answer might be as simple as that?
Electric water pump: Installed in the radiator hose somewhere, I heard
they work well - but have not seen details of these for a while. Used as an
auxilliary fan. Looking on the net I found for $350: EMP Stewart
Components Electric Water Pump. Also: “Inline Booster Pump - Stewart’s
inline booster pump is intended for vehicles that experience overheating
problems in low RPM situations. Since mechanical water pump speed is
directly linked to engine speed, overheating becomes a major problem in
situations such as parades, cruises, and stop-and-go traffic. The inline
booster pump solves this problem by working in conjunction with the
mechanical pump to create constant added flow to the engine block; the pump
has been proven to increase flow by more than 300% at idle! These pumps are
currently being used by NHRA Pro Stock Champion Warren Johnson and Kurt
Johnson by Dart Industries, and Jim Yates - as well as road racing American
Lemans and SCCA World Challenge. Code: E558A Price:$404.70”.
Variable pitch fan: Offered by XKs Unlimited at a huge price - over
US$500 I think. I emailed them for info about the specifications and tests
as to performance - and never got a reply. So it is not possible to count
on that as a solution - unless one of you guys knows better?
Alloy radiator: One owner said it made no difference. Another workshop
could not explain to me why it would help. Does not seem to be a solution,
I guess you use one to save weight and because I was told that making one
was no dearer than making a steel / copper / whatever one, from scratch.
My car cools perfectly when I am driving but starts to overheat when
standing still. The cause is easily observed, since I have the beautifully
sculptured but ineffective cast aluminum boat propellor fan with no shroud.
The problem is a lack of airflow when the car is stopped, which can only be
improved by improving the fan or adding a new one.
For some reason, fans behind the radiator are said to be somewhat more
efficient. However, you would need to remove the existing fan, and that
would require the electric fan to be on most of the time. My guess is that
overall electrical consumption would be higher with that configuration, so
overall your efficiency would be lower. Myself, I bought an electrical fan
to mount in front of the radiator that I can switch on when necessary.
More water circulation will not help unless you have enough airflow to
cool the water. See #1.
You can buy several electric fans for that price, with the advantage that
they only make noise when they’re switched on.
Weight savings only.
I’d leave the oil alone. Oil needs to be hot in order to boil off the
volatiles such as water and unburned fuel. It takes long enough to heat all
that oil up anyway, so adding a cooler (unless you are racing at LeMans) is
not a good idea. You want your head cool but your oil hot, so cool the
water.
Mike Eck
New Jersey, USA
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2> I have the usual 120 problem of overheating in traffic. I would welcome
comments / help from those of you who have dealt with the problem. I have
had the radiator dismantled and cleaned and the original water pump
reconditioned. Comments so far:
In reply to a message from John Elmgreen sent Wed 17 Dec 2008:
With my 120 DHC, I have NO overheating problems. I can sit in
South Florida traffic in July and not overheat.
The following has been done to my car:
1, Stock radiator has been recored with a modern high effficiency
core. Many radiator shops make their own cores, find one and
demand the highest efficiency one. Cost $350.00 Shop claimed a
40% improvement in cooling efficiency IE heat rejection.
2, Stainless steel flex fan, I don’t recall where I bought it but
it works. I know that I did not spend anywhere near $500.00 for
sure. Your stock cast aluminum fan is useful to stir the air up a
little bit, but no more. Perhaps if you wish to remain nearly
stock you could find a later 120’s multi blade fan.
3, I use a blend of 30% anti freeze, 70% distilled water plus the
recommended amount of Red Line Water Wetter. (Anti freeze is NOT a
good medium for transferring heat. Water is.)
4, I use a 6 lb radiator cap (from NAPA)
5, Around the radiator sides, top and bottom, I use air
conditioner foam blocks to seal off the engine bay from the grill
area. This so that no hot air can re-circulate, so you get all the
cooling air from the grille.
Hi, not trying to steal Joel’s thunder, but he has stated several
times that one could install an “E” core in his radiator to obviate
such occurrences. That “E” stands for Emergency - as in ambulances,
police cars, etc. I’m sure he’ll say this when he chimes in. Mea
culpa, Joel.
In reply to a message from John Elmgreen sent Wed 17 Dec 2008:
Hi John,
Like you, I considered all of the options on your list, and chose
some that are on it and others that are new.
I had my original radiator recored from a single to a triple core
radiator. Cost was about $300. Much less than the aluminum one.
I also replaced the waterpump with a rebuilt unit from Bassett and
installed a Flex fan. My other fan lost a blade so it was time to
upgrade.
As a result, overheating is a thing of the past, temp staying on
the cool side, even in 90 degree weather.
Other things to check are the seal under the radiator cap, often
missing, it is 1/8’’ nitrile rubber , 1-3/8 ID and 2-1/4 OD. There
are nibs on the radiator neck to hold it in place.
Another easy to install item is an overflow bottle, around $8 at
the discount shops and easy to hide under the fender out of sight.
When water is lost via the overflow tube, it can be overlooked and
the result is overheating.
Hope this helps, Cheers, Lee Jacobsen, Dearborn, MI–
XK120 OTS SE S673476, XK120 OTS SE S672814
Dearborn , MI, United States
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In reply to a message from Lee Jacobsen sent Wed 17 Dec 2008:
John,
My XK140 overheated, mainly because the old radiator was
old/plugged. I rebuilt with a high-efficiency core, and the problem
went away, except during traffic jams on the hottest days in Los
Angeles. I assume a fan would have helped.
In a related story, my Bora overheated, again because the old
radiator got gradually more and more plugged. I replaced the copper
radiator with an aluminum unit, and the temperature dropped big-
time! Also, I added two SPAL fans that crank 2,750 CFM combined.
Between the two, I can idle all day long in the hottest weather
without any worries.
So, my personal opinion is that aluminum radiators outperform
conventional copper radiators. Also, fans are a huge benefit if
you’re ever stuck in a traffic jam.
Note that big fans use big amps, so you might have to upgrade your
charging system. I replaced the alternator with a 140-amp unit on
the Bora, and had to wire in relays for each fan. However, if you
intend to actually use your car, cooling upgrades improve the
overall experience greatly.
Note: I don’t know how the ‘‘alloy’’ radiator morphed into an ‘‘oil’’
radiator within the lifespan of the above thread, but I don’t think
an oil radiator would make as much difference as getting the water
cooling set straight.
Aluminium is a fantastic conductor of heat, much better than copper.
Try cutting a bit with an plain old hacksaw and carefully feel the heat.
When machining coolant is needed to stop it virtually welding to the
tool.
DJOn 17 Dec 2008, at 23:54, Dave Shaw wrote:
In reply to a message from Lee Jacobsen sent Wed 17 Dec 2008:
John,
My XK140 overheated, mainly because the old radiator was
old/plugged. I rebuilt with a high-efficiency core, and the problem
went away, except during traffic jams on the hottest days in Los
Angeles. I assume a fan would have helped.
In a related story, my Bora overheated, again because the old
radiator got gradually more and more plugged. I replaced the copper
radiator with an aluminum unit, and the temperature dropped big-
time! Also, I added two SPAL fans that crank 2,750 CFM combined.
Between the two, I can idle all day long in the hottest weather
without any worries.
So, my personal opinion is that aluminum radiators outperform
conventional copper radiators. Also, fans are a huge benefit if
you’re ever stuck in a traffic jam.
Note that big fans use big amps, so you might have to upgrade your
charging system. I replaced the alternator with a 140-amp unit on
the Bora, and had to wire in relays for each fan. However, if you
intend to actually use your car, cooling upgrades improve the
overall experience greatly.
Note: I don’t know how the ‘‘alloy’’ radiator morphed into an ‘‘oil’’
radiator within the lifespan of the above thread, but I don’t think
an oil radiator would make as much difference as getting the water
cooling set straight.
In reply to a message from John Elmgreen sent Wed 17 Dec 2008:
You might also check your thermostat. Drop to a 160 degree if it
is higher than that now. If you could find a ‘‘Texas Cooler’’ and
install it, (they were multi blade high grade plastic generally
available for Austin Healey overheating)it increases air flow
significantly at idle and eliminated overheating on mine.–
Oppie
Navarre, Florida, United States
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Radiation is higher for aluminum but thermal conductivity (flow of eneregy through the mass) is higher for copper. Please see note from computer geeks:
There are a few substances that are at the top of the thermal conductivity charts, namely:
Diamond (2300 W/mK)
Pyrolytic Graphite (1950 W/mK)
Silver (429 W/mK),
Pure Copper (401 W/mK), and
Pure Aluminum (237 W/mK).
The first two are cost and geometrically prohibitive and are thus not candidates that will be looked at. Alloys of silver, aluminum and copper will always have a lower thermal conductivity than their pure counterparts, and often have thermal conductivities much lower. Thus it is very important to use pure metals! I.E. 6061 aluminum alloy will perform much worse than pure aluminum.
Aluminum is the most common heatsink material because of its cost, low density, availability, and machinability. Copper is beginning to become more popular but is much more difficult to work with and has a density approximately three and a half times that of aluminum. There has been talk recently of some silver heatsinks and/or waterblocks that may prove to be very interesting should they be able to be produced cost effectively.
Assuming that a system is constantly outputting heat, the material with the higher thermal conductivity will better move the heat away from the heat source. In the case of aluminum vs. copper, assuming identical geometries, copper will more effectively move the heat away from the point of contact with the CPU and into the extremities of the heat sink. This will give the heatsink a higher average temperature overall.
What you proved was that new aluminum radiators outperform old, plugged
copper radiators. No one is contesting that.
Mike Eck
New Jersey, USA www.jaguarclock.com
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2
In a related story, my Bora overheated, again because the old
radiator got gradually more and more plugged. I replaced the copper
radiator with an aluminum unit, and the temperature dropped big-
time!
So, my personal opinion is that aluminum radiators outperform
conventional copper radiators.
I won’t repeat myself here, but see my previous post:
Basically, Al beats Cu because of its strength–allowing
bigger tubes. This advantage outweighs the lower thermal
conductivity of Al compared to Cu.–
The original message included these comments:
Radiation is higher for aluminum but thermal conductivity (flow of eneregy through the mass) is higher for copper. Please see note from computer geeks:
In reply to a message from Brian Ternamian sent Wed 17 Dec 2008:
Thank-you Brian, I couldn’t have said it better myself. As a point
of reference, Th’‘E’’ type core is five rows with 14 louvered fins
per square inch, and it is made of copper. I’m not as familiar with
the 120 water pump as I am with the 140 WP, but another trick is to
restrict the by-pass with a disc with a 3/16’’ hole in the center.
The original thermostats closed off the by-pass once they opened,
but after 50+ years that area of the housing is such that a good
seal between the thermostat sleeve and housing ain’t what it used
to be. Consequently, when the sleeve retracted to block off the by-
pass, too much coolant was able to slip past. The disc with the
3/16’’ hole in it assures a greater amount of coolant is directed
through the radiator, and not just recirculated through the engine.
In the heat of a Texas summer, crawling along in a parade, my car
has yet to exceed 190F. I have also replaced the standard fan with
a 16’’ electric fan behind the radiator. A flex fan works well, but
you need a special adaptor to fit the bolt pattern and move the fan
far enough forward to clear the fan belt. That’s why the flex fan
kit is so high.
Joel–
The original message included these comments:
Hi, not trying to steal Joel’s thunder, but he has stated several
times that one could install an ‘‘E’’ core in his radiator to obviate
such occurrences. That ‘‘E’’ stands for Emergency - as in ambulances,
police cars, etc. I’m sure he’ll say this when he chimes in. Mea
culpa, Joel.
Best. Brian
In reply to a message from Robert Wilkinson sent Wed 17 Dec 2008:
Bob
A radiator’s efficiency is determined by how much heat can be
removed from the liquid in a given space and time. There is no
argument that it takes four 1/2’’ tubes to equal the flow of a 1’’
tube, but the surface area of the four 1/2’’ tubes is twice that of
the 1’’ tube offering the same flow. Therefore, theoretically, the
four 1/2’’ tubes have the ability to remove twice the heat of a 1’’
tube. Also, if the coolant is moved through the radiator too
quickly, a lesser amount of heat is removed. Hence, with volumes
being the same, the radiator with more tubes (even though they are
smaller), wins. Painting the radiator core, although it looks
pretty, will create a greater inefficiency than its composition (Al
or Cu).
Joel–
The original message included these comments:
Basically, Al beats Cu because of its strength–allowing
bigger tubes. This advantage outweighs the lower thermal
conductivity of Al compared to Cu.
Bob Wilkinson, 72 XJ6
In reply to a message from ex jag sent Wed 17 Dec 2008:
As stated in my previous post, it takes not four but sixteen
1/2 inch tubes to flow like one 1 inch tube–so there IS an
argument that it takes only four. This is approximate–the
tubes are flattened. As such, the surface area (over which
the air flows) is doubled for the one inch tubes compared to
two 1/2 inch tubes–no gain (or loss) there. It’s the
radius to the inverse fourth power flow resistance that
favours the larger tubes–which in turn requires the use of
Al for strength.
Ignoring frictional heating of coolant, the faster it flows
the better. Thinking slower is better is a common
misconception (discussed recently on the XJ forum). It is
correct if you want to cool the coolant. But if you want to
cool the engine, higher flow rate gives lower engine
temperature for a given radiator.–
The original message included these comments:
A radiator’s efficiency is determined by how much heat can be
removed from the liquid in a given space and time. There is no
argument that it takes four 1/2’’ tubes to equal the flow of a 1’’
tube, but the surface area of the four 1/2’’ tubes is twice that of
the 1’’ tube offering the same flow. Therefore, theoretically, the
tube. Also, if the coolant is moved through the radiator too
quickly, a lesser amount of heat is removed. Hence, with volumes
In reply to a message from Robert Wilkinson sent Wed 17 Dec 2008:
The 16 to 1 ratio based on the Navier-Stokes equation would be
correct if the tubes were cylindrical, but now we are applying this
law to flattened tubes. The surface area of a cylindrical tube
doesn’t change when it is flattened, but the volume does. The flow
rate through a flattened tube will be predicated on just how flat
it is. Either way, the limited capacity of the 120 and 140 water
pumps, and reduced coolant flow through the head, as compared to
the later XJ, would negate the advantage of a high flow radiator,
unless said radiator enabled a higher volume of coolant. I like the
advantages of the single row aluminum radiator. Unfortunately, as a
core that can be successfully attached to the tanks of the XK, it
just won’t work. But, and ‘‘E’’ type core is available at less than
half the cost of an aluminum radiator, and there is no way your car
will ever overheat. Problem solved. Good input Bob, thank-you, and
keep it up. We all benefit from good information such as what you
have provided.
Joel–
The original message included these comments:
As stated in my previous post, it takes not four but sixteen
1/2 inch tubes to flow like one 1 inch tube–so there IS an
argument that it takes only four. This is approximate–the
:Listers:
pardon me for my lack of knowledge…
can the radiator be re cored and add one more row?
i did this with my austin healey and it is not noticeable and works terrific.
is there room for another row in the 120 ? 140? 150?
ron rader
xk 150 FHC stock radiator (at the moment)
E type with Ron Davis alum radiator and A/C (radiator runs cold in AZ
with the a/c on)
1968 BJ8 4 core rad - runs very cold at all times.**************************************************
On Wed, Dec 17, 2008 at 9:52 PM, ex jag jcrprops@sbcglobal.net wrote:
In reply to a message from Robert Wilkinson sent Wed 17 Dec 2008:
Unfortunately, as a
core that can be successfully attached to the tanks of the XK, it
just won’t work. But, and ‘‘E’’ type core is available at less than
half the cost of an aluminum radiator, and there is no way your car
will ever overheat.
In reply to a message from F. Ronald Rader sent Wed 17 Dec 2008:
Ron
Yes. The five row ‘‘E’’ type core will fit the 120,140 and 150 tanks.
It is a little thicker (maybe a 1/4’’ or so), but a good radiator
shop can make it fit with a stronger seal than the original had.
Joel–
ex jag, '66 E-type S1 4.2, '56 XK140dhc, '97 XJ-6
Denison, TX, United States
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Sorry Mike what I wrote was gibberish.
I was trying to say aluminium RADIATORS are a fantastic conductor of
heat, much better than copper.
However at 1am my brain screwed it up so the while thing was nonsense.
The essence is that they seem more efficient for the reasons I suspect
Bob Wilkinson gives.
Apologies.
DJOn 18 Dec 2008, at 01:24, Mike Eck wrote:
Come again? Would you please quote your source, because all my
manuals say
that Al has a thermal conductivity of 250 while the value for Cu is
401.
Copper conducts heat 1.6 times BETTER than aluminum.
Mike Eck
New Jersey, USA www.jaguarclock.com
'51 XK120 OTS, '62 3.8 MK2 MOD, '72 SIII E-Type 2+2
Aluminium is a fantastic conductor of heat, much better than copper.