[DeTomaso] Fwd: gumball pantera purging air from cooling system

clarkewilma cwhamm at frontier.com
Tue Oct 25 14:54:27 EDT 2011


Hi,
My Pantera is completely stock. Fans, radiator, water pump, and engine. If
what you are saying. Cooling increases with the increased flow of coolant.
Then if there were no thermostat in the system there would always be less of
a chance for overheating. Understanding that a preferred running temperature
of 190 is desirable. My thought is that a quick trip to an area that is very
hot, such as the Fun Rally of next year, in which the temperature could get
close to the 100 degree mark and the track temperature up there also for a
stock car with lousy cooling anyway it would be an option. Thanks
Regards CRHAMM
      

-----Original Message-----
From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com] On
Behalf Of michael at michaelshortt.com
Sent: Monday, October 17, 2011 7:38 AM
To: LEVITT1946 at aol.com
Cc: DeTomaso Forum
Subject: [DeTomaso] Fwd: gumball pantera purging air from cooling system

OK, here is more info, I stand by my mix, if it's good enough for airplanes,
it's good enough for me.


*Coolant Mix and Overheating*
*

The problem:

Sometimes a water-cooled engine such as the Rotax 582 seems to run hotter
than it should, for no apparent reason. An identical engine installed the
same way in another plane may be fine, but one runs hot, and the other
doesn't. This problem can cause no small amount of hand-wringing and head
scratching, but as mysterious as it may seem, it may be quite simple to fix.

Now, more precisely, the situation we're talking about is this: the coolant
temperatures may run up to the 180 - 190 F range as opposed to the more
reasonable 165 - 175 F. Our radiator may be no smaller than someone else's
that works just fine, and the thermostat is not stuck or obstructed. It just
runs hot.

The problem might be that the coolant mix is too rich. That is, too much
"antifreeze" and not enough water. And to no one's surprise, what you do to
fix it is take out some of the antifreeze and replace it with water.
Reducing the mix ratio can easily lower the temperature by 15 F.

Why a rich mix gives less cooling:

First of all, in this article, we refer to the stuff you buy simply as
"antifreeze." It comes under many different trade names, and for automotive
applications, is usually ethylene glycol. We'll just call it "antifreeze."

Now if you've ever poured the stuff into a radiator, you no doubt observed
that it is much "syrup-i-er" than water. That is, it has a much higher
viscosity. This means that it will not flow as fast through the system as
water, and the cooling effect will be less.

Further, the specific heat of antifreeze is less than that of water. This
means that for a given temperature change, the antifreeze will carry less
heat each time it circulates from engine to radiator and back.

So, if the mix is too rich, the cooling efficiency will be reduced because
(1) the flow rate is less, and (2) less heat is transferred per cycle of the
coolant.

The manufacturer's recommendation:

The standard recommendation is to use a 50/50 mix of antifreeze and water.
This represents a compromise between cooling efficiency and the ability to
prevent the mix from freezing during cold weather. After all, the initial
purpose of antifreeze is to prevent freezing.

But a 50/50 mix does not give the best cooling. For improved cooling in hot
weather, we should use less antifreeze and more water, perhaps going to a
25/75 or a 20/80 mix ratio.

Everyone knows antifreeze prevents corrosion, and corrosion is bad. True
enough. But, even a 10/90 ratio of antifreeze to water will serve the
puproses of inhibiting corrosion, at least according to one source of
information.

More is better!

Not in this case. When you're adding the coolant to an engine, especially to
an aircraft engine, you want to do it as good as it can be done. Cut no
corners! Don't use just a little if a lot will do. After all, the stuff
coming out of the jug looks high-tech and scientific, and it's expensive, so
it must be good. Therefore, use a lot!

Yes, the stuff is good, high-tech, and all that, but it's physical
properties are not as good as plain, pure water when viewed from the point
of cooling. Therefore, you must resist the temptation to put in more just
because more seems like it should be better.

Results:

Temperature drops ranging from 10 - 15 F are typically obtained by
decreasing the mix from 50/50 down to 25/75 or perhaps 20/80. It is not
possible to give precise numbers here because of uncertainty in knowing
exactly what the initial mix was, and so forth.

In one instance, the original mix in a newly-purchased plane appeared to be
pure antifreeze. When the mix was changed to 25/75, the temperatures dropped
by 20 F! Here's the email that reported the results:

Hi Doc,

Well it worked perfectly and I got a 20 degree reduction in water temp by
decreasing the mix to 25/75. By the looks of the stuff that came out, I
really think that it was full strength antifreeze.

Unfortunately it will not be running any time soon. I had an engine failure
due to a poor gas tank vent design and didn't see a two strand barbwire
fence on the landing. I caught the left landing gear on a post and ripped it
off. Needless to say, the rest is self evident. But then that is another
story.
Thanks Again,
Al


Adjusting the mix, starting from scratch:

Determining the amounts of antifreeze and water is not particularly
difficult if you're filling a completely empty cooling system. The following
amounts are calculated for a system whose total volume is 8 units, whether
pints, liters, quarts, or whatever. (The total volume of a Rotax 582 system
is about 8 pints in typical installations.)

   Mix Ratio         Antifreeze         Water

       50/50                    4                      4
       40/60                 3.2                   4.8
       33/66                 2.6                   5.4
       25/75                 2.0                   6.0
       20/80                 1.6                   6.4
       10/90                 0.8                   7.2

If your system capacity is more than 8 units, say 10 for example, just
multiply each number in the table above by 10/8 = 1.25.

If your system capacity is less than 8 units, say 6 for example, just
multiply each number in the table above by 6/8 = 0.75.

Reducing the mix, starting with a 50/50 mix ratio:

If the system is already filled with coolant, what you must do is drain part
of the mix and replace it with pure water. Based on a system whose total
volume is 8 units, here are the amounts to drain in order to lower the mix
ratio from 50/50:

   New Mix Ratio         Drain and Replace

           40/60                           1.6
           33/66                           2.75
           25/75                           4.0
           20/80                           4.8
           10/90                           6.4

If your system capacity is more or less than 8 units, you can adjust these
numbers the same way as described above.

Reducing the Mix, general case:

This involves draining a fraction of the coolant and replacing it with pure
water as before. The amount to be drained out can be calculated if we know
the mix ratio of the coolant presently in the system and the total system
volume. The calculation is illustrated in the following.

First, express the mix ratio as a percentage, like this:

   Mix Ratio         Percentage

       50/50                   50
       40/60                   40
       25/75                   25       .... and so forth.

We have two different mix ratios to deal with. One is the mix ratio of the
coolant in the system now. We'll call this the OLD mix ratio.

The other is the mix ratio we're trying to get. We'll call it NEW.

The formula for finding how much to drain and replace with water is

   Drain = TotVol x ( 1 -- NEW / OLD )

where Drain is the amount to be drained out, and TotVol is the total volume
of the cooling system.

Example:

Suppose we have a system whose total volume is 10 pints and the mix ratio of
the coolant in it now is 60/40.

That is, it has more antifreeze in it than water. We want to reduce the mix
to 20/80. How much of the coolant should we drain and replace with water?

   Mix ratios, in percent:         OLD = 60         NEW = 20

   TotVol = 10 pints

   Drain = TotVol x ( 1 -- NEW / OLD )

   = ( 10 pints ) x ( 1 -- 20 / 60 )

      = ( 10 pints ) x ( 1 -- 0.333 ) = ( 10 pints ) x 0.667

      = 6.67 pints

Therefore, if we drain 6.67 pints of the original coolant and replace it
with pure water, the new mix ratio will be 20/80. And that's it.

An obvious final comment:

If you live in an area where the temperatures fall below freezing, you will
need to increase the mix back to a higher value before winter sets in. Which
is to say, you will need the antifreeze to prevent the system from freezing
up. But in cooler weather, it is unlikely that overheating will be a
problem. It would be a shame to forget to change the mix.

Credits: Thanks to my instructor and flying buddy, Mr. Ted Clement, for
sharing this information. He's a gentleman, a scholar, and he doesn't fly
all that bad either.

*
---------- Forwarded message ----------
From: michael at michaelshortt.com <michaelsavga at gmail.com>
Date: Mon, Oct 17, 2011 at 10:26 AM
Subject: Re: [DeTomaso] gumball pantera purging air from cooling system
To: LEVITT1946 at aol.com


I will research the mixture question before I offer an opinion on the
difference in temps making a difference in the ratio.
My mixture was a result of research based on optimum cooling and
heat dispersion.

I filled at level, let it run, then cut it off, jack it up and started the
whole process I told you about.

I did not jack up the front, that seems counterproductive to me, any trapped
air has no place to go.



On Mon, Oct 17, 2011 at 10:20 AM, <LEVITT1946 at aol.com> wrote:

> **
> I think I need more antifreeze being in New York. Winter is coming so
below
> freezing weather is just around the corner .
>
> 33/67 does not give me much freezing protection.
>
> Did you raise the rear of the car when filling ? After filling did you
> raise the front of the car as well?
>
> Bob
>
>  In a message dated 10/16/2011 11:34:16 P.M. Eastern Daylight Time,
> michaelsavga at gmail.com writes:
>
> 33% anti freeze, 67% water.
>
> i filled mine up, let it run while up in the air with the tank lid off,
> waited for the thermostat to open, topped it off unitl it overflowed, ,
then
> capped it, lowered the car. turned it off. let it cool. opened up the
tank,
> added more, let it run until it opened again, topped it off. capped it.
> turned it off.  Haven't touched ot since.
>
> Michael
> On Oct 16, 2011 9:57 PM, <LEVITT1946 at aol.com> wrote:
>
>> **
>> WHAT IS  33AF/67
>> RADIATOR IS ONE YEAR OLD
>> RADIATOR IS CLEAN
>> YES I JACKED THE CAR UP IN THE REAR .
>>
>> AFTER IT IS FILLED SHOULD YOU JACK UP THE FRONT AS WELL?
>>  In a message dated 10/16/2011 1:32:56 P.M. Eastern Daylight Time,
>> michaelsavga at gmail.com writes:
>>
>> I went through all of this in the last year, IMHO you have air in your
>> system, your 50/50 mix should be 33af/67 distilled water and water
wetter.
>> How old in the radiator?  Has it ever been cleaned?  Do you fill it and
run
>> it with the rear end jacked up at least 15"?
>> After having mine boiled, the mix above installed and de airred.  I can
>> sit in traffic on a 100 degree day At 170 and run it hard and never cross
>> 185.  Prior to that, i was constantly above 200, 220 in traffic and to
wary
>> to push it.
>>
>> Michael
>> On Oct 16, 2011 12:46 PM, <LEVITT1946 at aol.com> wrote:
>>
>>> Dear Friends,
>>>
>>>
>>> My Cooling system is set up as follows;
>>>
>>> fluidyne radiator leaning forward
>>>
>>> sucker fans on ALL the time
>>>
>>> Antifreeze  50/50 blend
>>>
>>> New High Flow Water pump
>>>
>>> 160 thermostat( correct for cleveland)
>>>
>>> I Used this tool to suck all air out of system and put the  antifreeze
>>> back
>>> in:
>>>
>>> UView 550000 Airlift Cooling  System Leak Checker and Airlock Purge Tool
>>> Kit
>>>
>>>
>>> On the open road the car runs at a  steady 180. As soon as I get into
>>> stop
>>> and go traffic or go from waiting at red  lights I can see the temp
gauge
>>> start climbing 220 plus . In the heat  of the summer months I feel like
>>> the
>>> car is ready to blow  hoses.
>>> I have read that guys here in the  group have cars that sit in the
desert
>>> sun all day and the temp gauge barely  moves. Either their gauges are
>>> broken
>>> or I have a system that the antifreeze is  just not flowing and cooling
>>> .When I bought the car three years ago the guy  said," If you are caught
>>> in
>>> traffic ,just pull over". I refuse to believe that  Detomaso designed
the
>>> car to
>>> overheat. I see Ferrari's,Lambo's and  Porsche run cool.So why can't the
>>> Pantera?
>>> I told my high temp issues to a  guy last week at one of the cruise in's
>>> and he said to me that back in the 70's  and 80's he developed a system
>>> that
>>> would lower the cooling temp by at least 20  degrees. He said that the
>>> cleveland engine in a pantera leans down at the  firewall and the heads
>>> will
>>> always get air trapped at the rear of the  head.(back of car) Causing
>>> there
>>> airlock situation and therefore  restricting flow.
>>> What he does is drill a hole  into each head and runs stainless lines to
>>> the pressure tank or  the the overflow tank,I forgot which one.
>>> Does this make sense to anyone ? Has  anyone every done this and had
>>> success?
>>> This guy did not seem like a typical  back yard mechanic .He designed
>>> this
>>> process while he was working for a speed  shop out here in New York
>>> called
>>> Motion.
>>> Please let me know your thoughts  .
>>> Regards,
>>> Bob Levitt
>>>
>>>
>>>
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>>>
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>>


-- 







Michael L. Shortt
Savannah, Georgia
www.michaelshortt.com
michael at michaelshortt.com
912-232-9390


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Savannah, Georgia
www.michaelshortt.com
michael at michaelshortt.com
912-232-9390


This email is protected by the Electronic Communications Privacy
Act, 18 U.S.C. Sec. 2510-2521, is confidential and may be legally
privileged.  If you are not the intended recipient, you are hereby notified
that any retention, dissemination, distribution or copying of this
communication is strictly prohibited.  Please reply to the sender that you
have received this message in error, then delete it.  Thank you
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