Yet another coolant question.
On a site that makes aluminum radiators for high performance cars I stumbled across a detailed document on how defective grounding in electrical system can cause electrolysis in the cooling system, disabling the anti corrosion additives and destroying their radiators (the crux of it was "test your cooling system for a voltage in the coolant before installing one of out radiators because if electrolysis ruins it we won't cover it under warranty."
Specifically, it said "A voltage of zero to .3 is normal in a coolant of cast iron engine. Such an engine will be destroyed with time by .5 volts, and engine manufactures are reporting .15 volts will destroy an aluminum engine. "
It said dip one probe of the voltmeter in the coolant(of course not touching the metal) and the other to ground.
So I went out to the hanger with a good voltmeter and with master electrical switch (and nothing else on) measured somewhere between 0.9 and 0.12 volts between the coolant and the heads. Depended a bit on exactly where I touched the heads.
I was and am curious if this is normal (as they did say it's normal to see as much as 0.3 volts in cast iron engines and IMPLIYED that up to 0.15 volts could maybe be normal in aluminum engines) or I have a potential problem .
I have never checked this before in the 2+ years 400 hours we've had this Rotax and doubt anyone ever did in the 9 years this 912 has been on our plane. This AFAIK isn't a check that's part of any annual or common inspection.
So I am inclined to believe this slight voltage difference has always been there.
So I called Prestone coolant tech support and talked to a tech who seemed pretty knowledgable about this issue.
His first response was that any voltage over 0.10 could be a problem, and that the thing to do would be to sequentially shut down all electrical components (radio, strobes, aux fuel pump, etc) and when one makes the voltage drop check for a poor ground in that sub system. But when I told him this was a voltage with no electrical sub systems on he asked if there was any Other reason to suspect electrical corrosion ...such as radiator seepage or signs of corrosion at visible grounding points.
When I told him "no" and none in 9 years he changed his take to saying it sounds like a "if it ain't broke don't fix it" issue.
So my questions are..
# has anyone here ever run this voltmeter check on your coolant in a 912 ?
# would anyone be willing to go out to the hanger..or maybe next time you pull the cowl off... or shop do so and report back what you find? (Once the cowl is off it takes only a few seconds to run this check, or if your Rotax is open rear mount even easier.
# anyone have any opinion, or better yet knowledge :) , of if this up-to-0.12 volts is something of concern...and if so how to address it?
All replies appreciated.
On a site that makes aluminum radiators for high performance cars I stumbled across a detailed document on how defective grounding in electrical system can cause electrolysis in the cooling system, disabling the anti corrosion additives and destroying their radiators (the crux of it was "test your cooling system for a voltage in the coolant before installing one of out radiators because if electrolysis ruins it we won't cover it under warranty."
Specifically, it said "A voltage of zero to .3 is normal in a coolant of cast iron engine. Such an engine will be destroyed with time by .5 volts, and engine manufactures are reporting .15 volts will destroy an aluminum engine. "
It said dip one probe of the voltmeter in the coolant(of course not touching the metal) and the other to ground.
So I went out to the hanger with a good voltmeter and with master electrical switch (and nothing else on) measured somewhere between 0.9 and 0.12 volts between the coolant and the heads. Depended a bit on exactly where I touched the heads.
I was and am curious if this is normal (as they did say it's normal to see as much as 0.3 volts in cast iron engines and IMPLIYED that up to 0.15 volts could maybe be normal in aluminum engines) or I have a potential problem .
I have never checked this before in the 2+ years 400 hours we've had this Rotax and doubt anyone ever did in the 9 years this 912 has been on our plane. This AFAIK isn't a check that's part of any annual or common inspection.
So I am inclined to believe this slight voltage difference has always been there.
So I called Prestone coolant tech support and talked to a tech who seemed pretty knowledgable about this issue.
His first response was that any voltage over 0.10 could be a problem, and that the thing to do would be to sequentially shut down all electrical components (radio, strobes, aux fuel pump, etc) and when one makes the voltage drop check for a poor ground in that sub system. But when I told him this was a voltage with no electrical sub systems on he asked if there was any Other reason to suspect electrical corrosion ...such as radiator seepage or signs of corrosion at visible grounding points.
When I told him "no" and none in 9 years he changed his take to saying it sounds like a "if it ain't broke don't fix it" issue.
So my questions are..
# has anyone here ever run this voltmeter check on your coolant in a 912 ?
# would anyone be willing to go out to the hanger..or maybe next time you pull the cowl off... or shop do so and report back what you find? (Once the cowl is off it takes only a few seconds to run this check, or if your Rotax is open rear mount even easier.
# anyone have any opinion, or better yet knowledge :) , of if this up-to-0.12 volts is something of concern...and if so how to address it?
All replies appreciated.
