[xj] antifreeze to water ratio

XJ
1

I recently checked my coolant with one of those Prestone gauges
I’ve had for at least 20 years. It indicated that I was at the very
top of the chart for protection.

My concern is - water is a much better conductor of heat than
antifreeze is. So, instead of just arbitrarily dumping 2 gallons of
Preston in the system on the next flush, I may try to shoot for a
little less antifreeze and a bit more water. Do I really need 265F
boil over protection and minus 34F freeze protection here in the SE
USA?–
Ted Macklin/'85 XJ6SIII
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

2

In reply to a message from TMack sent Sat 6 Dec 2008:

Ted:

That guage, as you know is a hydrometer and measures the specic
gravity of the mixture. I have one also, largely unused.

I just roughly compute a 50/50mix and let it go at that!

No, you are not likely to approach those temperatures in your area.

Carl–
The original message included these comments:

I recently checked my coolant with one of those Prestone gauges
I’ve had for at least 20 years. It indicated that I was at the very
top of the chart for protection.
My concern is - water is a much better conductor of heat than
antifreeze is. So, instead of just arbitrarily dumping 2 gallons of
Preston in the system on the next flush, I may try to shoot for a
little less antifreeze and a bit more water. Do I really need 265F
boil over protection and minus 34F freeze protection here in the SE
USA?

–
Carl Hutchins 1983 Jaguar XJ6 with LT1 and 1994 Jeep Grand
Walnut Creek, California, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

3

In reply to a message from cadjag sent Sat 6 Dec 2008:

50/50 is the preferred, I know.

But my point is, I wonder if I would get better cooling efficiency
with something less than the maximum - minus 34F protection?

There’s always some fluid left inside my system after a flush, it’s
just impossible to completely drain it IMO. That said, the 2
gallons of pure antifreeze which I always dump in there first might
be too much - by the time I top it off with water?? In other words,
I don’t remember ever being able to get 2 gallons of water in there
after pouring in the 2 gallons of antifreeze. Yet the capacity is
listed as 4 gallons IIRC.

Yours for better cooling!

TM–
The original message included these comments:

I just roughly compute a 50/50mix and let it go at that!

–
Ted Macklin/'85 XJ6SIII
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

4

In reply to a message from TMack sent Sat 6 Dec 2008:

The latest great idea from the antifreeze companies is to
offer ‘pre-mixed’ antifreeze (a 50/50 mix of glycol and water) for
$13.95 a gallon. Straight glycol – the kind you have to mix
yourself – sits on the shelf right next to it at $15.95 a gallon.
I had no idea water was that expensive! It must be mixed with
Evian (‘naive’ spelled backwards)–
The original message included these comments:

My concern is - water is a much better conductor of heat than
antifreeze is. So, instead of just arbitrarily dumping 2 gallons of
Preston in the system on the next flush, I may try to shoot for a
little less antifreeze and a bit more water. Do I really need 265F
boil over protection and minus 34F freeze protection here in the SE
USA?

–
Pete Peterson 70E(193K) 88 XJ40(250K) 88 XJ40(239K) 94 XJ40
Severna Park, Maryland, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

5

In reply to a message from TMack sent Sat 6 Dec 2008:

I obsess over precisely this kind of stuff. Glycol and the
other corrosion inhibitors, etc. in antifreeze protect the
engine and more is better. Industrial applications often
use 100%, but are designed for adequate thermal performance
even though specific heat is less than that of water or a
mix. Conversely, some racers use pure distilled/deionized
water, plus RedLine water wetter. They get maximum thermal
performance, noting that even though pressures will be much
higher above 100C, the engine won’t get as far above 100C
due to the increased cooling capacity.

Reading the literature, it seems that a range from 30%
antifreeze to 50% antifreeze is used. The lower
concentrations are suitable for milder climates, and/or to
increase cooling capacity, and/or to decrease cost. The
higher concentrations are required for some climates, and
preferred if there are no overheating problems.

In all cases, coolant should be changed to renew the
additives it contains, even if it appears clean.

In Saint Louis I use 40% antifreeze plus water wetter.–
The original message included these comments:

My concern is - water is a much better conductor of heat than
antifreeze is. So, instead of just arbitrarily dumping 2 gallons of
Preston in the system on the next flush, I may try to shoot for a
little less antifreeze and a bit more water. Do I really need 265F
boil over protection and minus 34F freeze protection here in the SE

–
Bob Wilkinson, 72 XJ6
Saint Louis, MO, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

6

In reply to a message from Robert Wilkinson sent Sat 6 Dec 2008:

That’s interesting, Bob. I’e always used a 50% solution more
because of the corrosion protection than the cooling capabilities
of the mix. I think that even if I lived in warmer climates, I
would still do so just to keep the inside of the rad and water
jacket cleaner.

I ususally pre mix before putting it in the engine. I buy a gallon
of coolant and a gallon of water. I keep old containers and mark
them 50/50 so I don’t get them confused. I have bought the
premixed on occasion just for the convenience. It’s a stupid waste
of money, but… well, it’s a stupid waste of money (-;–
The original message included these comments:

I obsess over precisely this kind of stuff. Glycol and the
other corrosion inhibitors, etc. in antifreeze protect the
engine and more is better. Industrial applications often

–
John Testrake 74XJ12L rhd, 84 XJ6 700R4
St.Louis, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

7

The minimum you’d want to go to is 30% glycol, and the maximum 70%. In
cold climates 70% provides the maximum freeze protection, as it is an
inverse bell shaped curve. An 80/20% mix freezes at a higher temperature
than 70/30.

For hot climates I’d go no lower than 30% for corrosion protection, but
that may be inadequate for boil over protection. You’d need to change
the coolant more frequently to continue the corrosion protection.

50/50 needs a radiator about 15% larger than pure water to shed the same
amount of heat.

Craig

TMack wrote:>In reply to a message from cadjag sent Sat 6 Dec 2008:

50/50 is the preferred, I know.

But my point is, I wonder if I would get better cooling efficiency
with something less than the maximum - minus 34F protection?

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

8

In reply to a message from Craig Talbot sent Sat 6 Dec 2008:

Through research and general reading on the subject I use no more
then a quart antifreeze then the rest water. You are right in that
water is better at doing the job.–
Milner
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

9

In reply to a message from TMack sent Sat 6 Dec 2008:

Ted

In my SII ROM the instruction is to use 55% antifreeze except in UK
where the concentration is given as 40%. I’ve no idea why, but if
it was considered safe here, it ought to be OK there as well?–
The original message included these comments:

I don’t remember ever being able to get 2 gallons of water in there
after pouring in the 2 gallons of antifreeze. Yet the capacity is
The original message included these comments:

I just roughly compute a 50/50mix and let it go at that!

–
al mclean '93 XJS 4.0 - '84 4.2 Daimler - '84 DD6
Telford, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

10

I always have used 40% (the rest distilled) in all our cars. If you
want to go skiing here though, 50% is recommended!–
Alex
79xj6L SII (BRG + wires)
86xj6 SIII (Black)
61 Sprite MkII (Red)
Menlo Park, Calif.

almcl wrote:

In reply to a message from TMack sent Sat 6 Dec 2008:

Ted

In my SII ROM the instruction is to use 55% antifreeze except in UK
where the concentration is given as 40%. I’ve no idea why, but if
it was considered safe here, it ought to be OK there as well?

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

11

In reply to a message from Alex Cannara sent Sat 6 Dec 2008:

Interesting post,
I recently posted a question requarding a problem I’m having with
over-cooling. This time of year my guage seldom gets much over the
50 degree mark.
I had replaced the water pump, cleaned the radiator, replaced the
thermostat, etc due to an overheating problem in the summer of 07.
Since then, it always runs extra cool.
But, looking back, I think I may have left only the coolant that
was actually in the engine and heater core, and had drained the
rest. When I put the car back together it seems that I may have
replaced it with only water, giving me about a 20% coolant mixtue
(maybe less if it were originally 50/50.)

I’d been planning to replace the thermostat to see if it were stuck
open, but maybe I just need an engine flush and the correct mixture
of coolant added (?).

David–
69 XJ6, 75 XJ12, 84 XJ6, Bunches of parts cars
Rockwell, NC, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

12

I think you have a faulty thermostat, David.

Gregory,
Victoria, Canada
1966 Mark 2 3.8 (Pale Primrose)
1992 Series III V12 Vanden Plas (Black Cherry)
2002 X-Type 5 sp. manual (Anthracite)
2004 XJ8 4.2 (Ebony)-----Original Message-----
From: owner-xj@jag-lovers.org [mailto:owner-xj@jag-lovers.org] On Behalf Of
DavidBoger
Sent: December-06-08 3:07 PM
To: xj@jag-lovers.org
Subject: Re: [xj] antifreeze to water ratio

In reply to a message from Alex Cannara sent Sat 6 Dec 2008:

Interesting post,
I recently posted a question requarding a problem I’m having with
over-cooling. This time of year my guage seldom gets much over the
50 degree mark.
I had replaced the water pump, cleaned the radiator, replaced the
thermostat, etc due to an overheating problem in the summer of 07.
Since then, it always runs extra cool

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

13

In reply to a message from Dr. Gregory Andrachuk sent Sat 6 Dec 2008:

I think you are probably correct Gregory, and I have that on my to
do list.
Does an open thermostat never allow the car to heat up, even after
it has been driven for several hours?

David–
69 XJ6, 75 XJ12, 84 XJ6, Bunches of parts cars
Rockwell, NC, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

14

DavidBoger wrote:

In reply to a message from Dr. Gregory Andrachuk sent Sat 6 Dec 2008:

I think you are probably correct Gregory, and I have that on my to
do list.
Does an open thermostat never allow the car to heat up, even after
it has been driven for several hours?

No, David…:slight_smile:

The only reason for the thermostat is to keep the engine hot, it’s the
only thing designed to do that - all other cooling sytem components are
there to keep the engine cool. Gregory is dead right; change the
thermostat - or verify that your dash gauge is correct…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

15

No, no, Frank, there are 3 more things that “keep the engine hot” –
air, fuel & spark.
;]–
Alex
79xj6L SII (BRG + wires)
86xj6 SIII (Black)
61 Sprite MkII (Red)
Menlo Park, Calif.

Frank Andersen wrote:

No, David…:slight_smile:

The only reason for the thermostat is to keep the engine hot, it’s the
only thing designed to do that - all other cooling sytem components are
there to keep the engine cool. Gregory is dead right; change the
thermostat - or verify that your dash gauge is correct…:slight_smile:

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

16

Coolant mix ratio can’t do that David – you need what Gregory says!
Test any thermo you put in first.–
Alex
79xj6L SII (BRG + wires)
86xj6 SIII (Black)
61 Sprite MkII (Red)
Menlo Park, Calif.

DavidBoger wrote:

In reply to a message from Alex Cannara sent Sat 6 Dec 2008:

Interesting post,
I recently posted a question requarding a problem I’m having with
over-cooling. This time of year my guage seldom gets much over the
50 degree mark.
I had replaced the water pump, cleaned the radiator, replaced the
thermostat, etc due to an overheating problem in the summer of 07.
Since then, it always runs extra cool.
But, looking back, I think I may have left only the coolant that
was actually in the engine and heater core, and had drained the
rest. When I put the car back together it seems that I may have
replaced it with only water, giving me about a 20% coolant mixtue
(maybe less if it were originally 50/50.)

I’d been planning to replace the thermostat to see if it were stuck
open, but maybe I just need an engine flush and the correct mixture
of coolant added (?).

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

17

Alex Cannara wrote:

No, no, Frank, there are 3 more things that “keep the engine hot” –
air, fuel & spark.
;]

Only the latter is related to the cooling system, Alex - and indirectly.
I kept this strictly to the cooling system - without the factors you
mention there is no need for a cooling system at all…:slight_smile:

Frank
xj6 85 Sov Europe (UK/NZ)===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

18

TMack wrote:

In reply to a message from cadjag sent Sat 6 Dec 2008:

50/50 is the preferred, I know.

But my point is, I wonder if I would get better cooling efficiency
with something less than the maximum - minus 34F protection?

There’s always some fluid left inside my system after a flush, it’s
just impossible to completely drain it IMO. That said, the 2
gallons of pure antifreeze which I always dump in there first might
be too much - by the time I top it off with water?? In other words,
I don’t remember ever being able to get 2 gallons of water in there
after pouring in the 2 gallons of antifreeze. Yet the capacity is
listed as 4 gallons IIRC.

Yours for better cooling!

Can’t beat heaps of cool, man…:slight_smile:

Glycol in itself is not a very effective corrosion inhibitor, which is
why anti-corrosive agents are added. The primary function of glycol is
frost protection, and is separate from corrosion protection. But a
specific amount of glycol, as bought, only contains so much inhibitors
and diluting it below say 30% is considered as corrosion
counterproductive - irrespective of climate. Ie, it is not so much the
less glycol but the excessive amount of water that is the point…

As Craig states; typically the inhibiting qualities of the additives
detoriorates over time/use, which is why regular coolant change is
recommended - irrespective of still correct glycol mix readings.

Now, in principle, where there is no frost pure water can be used -
provided correct inhibitors are added. However, exactly what is then
required is not generally publicised - while glycol data are…:slight_smile:

So, while pure water may cool more effectivel I’m not too sure if 30%
glycol will make more than a marginal difference…?

Frank
xj6 85 Sov Europe (UK/NZ)===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

19

In reply to a message from Frank Andersen sent Sun 7 Dec 2008:

In my fading memory, I seem to remember owning some PH strips
(from Prestone?) that would allow me to measure corrosion
protection levels. This was 20 years ago or more.

Advanced Auto had nothing like it when I asked the clerk recently.
But I haven’t looked any further. Guess I could Google it…but -
does anyone know what I’m talking about??–
The original message included these comments:

Glycol in itself is not a very effective corrosion inhibitor, which is
why anti-corrosive agents are added. The primary function of glycol is

–
Ted Macklin/'85 XJ6SIII
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: Jag-lovers Forums - Jag-lovers

To remove yourself from this list, go to Jag-lovers Forums - Jag-lovers.

// please trim quoted text to context only

20

That depends on conditions. The engine will warm, but not to the proper
temperature, and that will mean that the fuel “mixture” will be richer than
it should be (depending upon the temperature reached) and there will be
increased engine wear. I once had a faulty thermostat in a 1984 Sovereign.
The engine reached about 60 degrees but would not go higher; replacing the
thermostat cured the problems instantly and improved the fuel economy and
performance.

Gregory,
Victoria, Canada
1966 Mark 2 3.8 (Pale Primrose)
1992 Series III V12 Vanden Plas (Black Cherry)
2002 X-Type 5 sp. manual (Anthracite)
2004 XJ8 4.2 (Ebony)-----Original Message-----
From: owner-xj@jag-lovers.org [mailto:owner-xj@jag-lovers.org] On Behalf Of
DavidBoger
Sent: December-06-08 5:58 PM
To: xj@jag-lovers.org
Subject: RE: [xj] antifreeze to water ratio

In reply to a message from Dr. Gregory Andrachuk sent Sat 6 Dec 2008:

I think you are probably correct Gregory, and I have that on my to
do list.
Does an open thermostat never allow the car to heat up, even after
it has been driven for several hours?

David

69 XJ6, 75 XJ12, 84 XJ6, Bunches of parts cars
Rockwell, NC, United States
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
–Support Jag-lovers - Donate at http://www.jag-lovers.org/donate04.php –

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to
http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only

===================================================
The archives and FAQ will answer many queries on the XJ series…
FAQs: http://www.jag-lovers.org/xjlovers/xjfaq/index.html
Archives: http://www.jag-lovers.org/lists/search.html

To remove yourself from this list, go to http://www.jag-lovers.org/cgi-bin/majordomo.

// please trim quoted text to context only