Paul,
 You might have solved part of a non-aero issue for me.  There's been large
increase in copper in oil analysis reports from diesel pickups.  One train
of thought has been induced voltages caused by multiple ground points - the
oil cooler in one circuit, the engine in another - causing electrolysis.
This suggests that the oil cooler can be electrically isolated from the
vehicle...until the coolant ages.  Cool!

  Do you think that either coolant changes OR hose changes would be enough
for us, while changing both gives redundancy?  Test strips are widely
available for checking coolant acidity, BTW.

Andy Hecker
San Antonio

The silicone hose has other advantages. The drawback is it cost a dollar in inch.

Paul Lamar

I ran into an engineer at OSH that works for Cummins I think.
He did not have a card on him but hopefully he will join
up as I gave him my card.

He told me the life limiting factor on a diesel engine is the cooling
system. When the antifreeze gets old it turns acidic.
When that happens black low cost automotive hose becomes part of a

battery

because of the conductive carbon in it. You can actually measure
the voltage with a digital voltmeter by putting one probe
on the hose and the other on the hose barb. The black hose
loses carbon to the mixture. This causes a reduction in strength
of the hose. The answer is silicone rubber hose and changing your
coolant once a year. This could be a factor in the two crashes
we have had due to cooling hose joint failures. In both cases the
people had been flying their rotary powered airplanes for several years.


Paul Lamar

 
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