We have lost two airplanes to stupid failed cooling hose connections.
Fortunately nobody was seriously hurt. A cooling system failure
can cause you to crash just as surely as a connecting rod breaking
(if we even had connecting rods). So pay attention.
Always use Breeze constant torque hose clamps or something similar
and silicone rubber hose.
-------------------------------------------------------------------f
Over the years I found that you can always test a system with a voltmeter as
the article suggests and you can actually see the system degrade with time
if you have the same vehicle present and you know its past. I used my own
vehicles as test vehicles to firm up my thought process. I would only change
one part of the article from my own field experience and that is the test
with an aluminum engine or some part of the engine being aluminum. The test
at .15 volts is too high on a Japanese engine I use .05 as acceptable,
anything higher as too high. Most cooling systems will test .00 when new or
fairly new. The tests for an electrical current are very good too but if
present the antifreeze will lose its additives rapidly. I would suggest you
get a voltmeter or multimeter and test a few cooling systems for your own
education and you can see the correlation.
A field test about 6 years ago was done by Gates Rubber Co in conjunction
with Texaco (antifreeze supplier) Cummins Diesel and Detroit Engine Co. The
purpose was to see if it was feasible to supply diesel engines that could be
guaranteed for one million miles without overhaul. The results were very
interesting with the cooling systems being the Achilles heel of the engines.
They found that if the antifreeze mix proportions were not 5O/50 they would
suffer from "precipate" damage to the water pump seals. That hose clamps
would always loosen with time and age and better clamps needed to be
incorporated, also that if the system went to an acidic condition it was
possible to leach the carbon black out of a rubber hose especially in a bend
and the fabric would be weakened and fail. All of the tests led to different
ways to make radiator host/shrink bands and antifreeze chemically different.
GM picked up on this test and changed the GM antifreeze which has increased
the change periods for their antifreeze. I hope I haven't confused you by
going on too much but I find cooling systems very interesting.
Best regards
[signed]
Wally Clingan
Hi Wally, very interesting, could you expand a little on how to do these tests?
Like: Where to put the test probes, and should the coolant be up to operating
temperature? It sounds like the test requires a very sensitive multimeter; mine
is rated at 20K ohms per volt, is that OK or do I need a Fluke or somesuch rated
at 50K O/V or better? Thank you for your contribution, we have a lot of theorists
on here, but few with your specialist background on engine cooling. Indeed,
Cooling is the Achilles Heel of Airborne Rotaries. BR, Dave McC
Wally Clingan Wrote:
Dear Paul
Temperature of the coolent doesn't seem to make a difference or the
type of voltmeter as long as the meter is able to read into the low
voltages. Digital and analog meters both work well.
Use your car or pickup when the engine is cold to try out the tests,
this will also tell you if you have a problem started or your
antifreeze needs to be changed. The voltmeter needs to be in the D.C.
scale set for a low voltage reading. Insert the positive lead into
the radiator coolent, liquid only ensure that the lead is not
touching any metal. Attach the negative lead to the battery ground,
if the lead is too short attach it to the best ground you can find.
You should see a reading of 00 volts to .3 volts (that is three tenths
of a volt) this reading is for a cast iron block engine. For an
aluminum block or partial aluminum block engine you should see 00
volts to .05volts (thats five hundreths of a volt. Higher readings
indicate the coolent is going acid and corrosion is occuring.
Next, with the leads still attached the same way, still using the
same D.C. scale on your voltmeter turn on all electrical components
that you can. Also crank the engine (note engine should be fixed to
not start) if you observe any readings that exceed the norms then
turn off each electric component and see when the reading drops; this
will be the offending component. If it is the starter this will
require additional grounding for the starter. Retest to see if
problem is corrected.
Hope this helps clarify this test it is really very simple, your
trying to find out if the coolent is going acid. Interesting I've
found bad starter grounds will eventually turn the coolent black and
tend to jell the coolent.
Please take me off the ACRE E mail list I only check my E mail once a
week and that does make it too much.
If you need further info or anyone still needs info then they can
contact me.
Wally Clingan
wallyclingan@stompit.net
Paul Lamar
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