Oil change.

[Tony Cox]

I changed the oil in my O470R this weekend. 24.5 tach hours
and 4 months from the last oil change. I use AeroShell 100W+,
which is a 50 weight ashless oil (the one with the gold coloured
label).

After flying around for an hour or so to warm it up before draining,
I happened to notice that oil on the dip-stick is 'beading', rather
like raindrops on a window pane.

Am I right in thinking that this oil has wetting additives that have
boiled off in use?

[Aaron Coolidge]

Tony Cox > wrote:
: After flying around for an hour or so to warm it up before draining,
: I happened to notice that oil on the dip-stick is 'beading', rather
: like raindrops on a window pane.

You're probably seeing some water condensed on the top of the dipstick
running back down. Burning gasoline results in some water being produced,
which eventually goes out the crankcase breather. Some condenses on the
top of the dipstick because it's probably the coolest point in the engine.

: Am I right in thinking that this oil has wetting additives that have
: boiled off in use?

I don't think it has such ingredients. Oil wets metal very well without
any assistance.
--
Aaron Coolidge

[Tony Cox]

"Aaron Coolidge" > wrote in message
...
> Tony Cox > wrote:
> : After flying around for an hour or so to warm it up before draining,
> : I happened to notice that oil on the dip-stick is 'beading', rather
> : like raindrops on a window pane.
>
> You're probably seeing some water condensed on the top of the dipstick
> running back down. Burning gasoline results in some water being produced,
> which eventually goes out the crankcase breather. Some condenses on the
> top of the dipstick because it's probably the coolest point in the engine.

I don't see this with 'fresh' oil. Also, being blessed to live in
Las Vegas where the humidity is usually in the teens, it's unlikely
that there is any water contamination.

>
> : Am I right in thinking that this oil has wetting additives that have
> : boiled off in use?
>
> I don't think it has such ingredients. Oil wets metal very well without
> any assistance.

Any idea what the additives in 100W+ are, Aaron? I suppose
one day I ought to find out why I'm paying an extra $0.50/qt
over straight 100W. Perhaps that day has come!

[Ron Natalie]

Tony Cox wrote:

> I don't see this with 'fresh' oil. Also, being blessed to live in
> Las Vegas where the humidity is usually in the teens, it's unlikely
> that there is any water contamination.

Read the response carefully. Burning fuel makes water. As a matter of
fact carbon dioxide and water are the predominant products of
hydrocarbon combustion (where do you think the hydro part goes ...)


>

[Tony Cox]

"Ron Natalie" > wrote in message
m...
> Tony Cox wrote:
>
> > I don't see this with 'fresh' oil. Also, being blessed to live in
> > Las Vegas where the humidity is usually in the teens, it's unlikely
> > that there is any water contamination.
>
> Read the response carefully. Burning fuel makes water. As a matter of
> fact carbon dioxide and water are the predominant products of
> hydrocarbon combustion (where do you think the hydro part goes ...)

You'll have to walk me through this Ron, because I still don't
get it. The flight to warm up the oil was just short of an hour.
I know that burning fuel creates some water & that it'll get into
the oil. But why am I seeing 'beading' in the old oil, but not the
fresh stuff? The only thing that can possibly be different is the
composition of the old oil compared to the new.

[Aaron Coolidge]

Tony Cox > wrote:
: "Ron Natalie" > wrote in message
: m...
:> Tony Cox wrote:

: You'll have to walk me through this Ron, because I still don't
: get it. The flight to warm up the oil was just short of an hour.
: I know that burning fuel creates some water & that it'll get into
: the oil. But why am I seeing 'beading' in the old oil, but not the
: fresh stuff? The only thing that can possibly be different is the
: composition of the old oil compared to the new.

Did you wipe off the dipstick when adding new oil? Perhaps you've wiped
off the little bit of water that's condensed there.

I also see a little bit of water droplets on the top of the dipstick
depending on weather and flight conditions. Right after a flight there are
no water drops, but wait a couple hours and a few show up.

The "Plus" in the oil is the Lycoming antiwear additive required for
certain Lyc engines. It's probably a good idea in any engine (the additive
is an extreme pressure lubricant, I have been told, to minimize cam
follower wear).
--
Aaron Coolidge

[Tony Cox]

"Aaron Coolidge" > wrote in message
...
> Tony Cox > wrote:
> : "Ron Natalie" > wrote in message
> : m...
> :> Tony Cox wrote:
>
> : You'll have to walk me through this Ron, because I still don't
> : get it. The flight to warm up the oil was just short of an hour.
> : I know that burning fuel creates some water & that it'll get into
> : the oil. But why am I seeing 'beading' in the old oil, but not the
> : fresh stuff? The only thing that can possibly be different is the
> : composition of the old oil compared to the new.
>
> Did you wipe off the dipstick when adding new oil? Perhaps you've wiped
> off the little bit of water that's condensed there.

Yes. Wipe, dip, check. Immediately after the flight. No water
to be seen. Instead of the oil adhering consistently to the
dip-stick, the old oil formed a sort-of 'river' up the stick leaving
some parts clear. It looked from the meniscus that it was
trying to form droplets. I should add that it wasn't just the
last flight before the oil change; the penultimate flight showed
the oil in the same condition too, now I think of it. It seems
that *something* that normally reduces the oil surface tension
had boiled off.

>
> I also see a little bit of water droplets on the top of the dipstick
> depending on weather and flight conditions. Right after a flight there are
> no water drops, but wait a couple hours and a few show up.
>
> The "Plus" in the oil is the Lycoming antiwear additive required for
> certain Lyc engines. It's probably a good idea in any engine (the additive
> is an extreme pressure lubricant, I have been told, to minimize cam
> follower wear).

I've heard that too. I use it in my Continental at the suggestion of my
A&P whose opinion I respect. More expensive, so it must be better,
eh?

[tony roberts]

> After flying around for an hour or so to warm it up before draining,
> I happened to notice that oil on the dip-stick is 'beading', rather
> like raindrops on a window pane.
>
> Am I right in thinking that this oil has wetting additives that have
> boiled off in use?

I don't think so. Seems to me that you had water in the oil.
I had it 2 weeks ago - first time. In my case I had the starter adapter
off for service and the engine wrqapoped in plastic.
AQfter my runup I n oticed the problem that you are having and took the
aircraft straight to the shop. They told me water in the oil - and as
the oil was new, go fly 45 minutes and it wouild boil off - which it did.

Tony
--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

[One's Too Many]

"Tony Cox" > wrote in message >...

>
> Any idea what the additives in 100W+ are, Aaron? I suppose
> one day I ought to find out why I'm paying an extra $0.50/qt
> over straight 100W. Perhaps that day has come!

The Lycoming anti-wear additive. Used to be TCP (Tri-Cresyl Phosphate)
until a few years ago when it was changed to TPP (Tri-Phenyl
Phosphate) when it became widely known that TCP was an extremely
neurotoxic poison that rapidly absorbs thru your skin. TPP is somewhat
less dangerous than TCP and works almost as well for protecting
against premature lifter/cam lobe wear.

Yes, this is the same TCP or TPP chemical that used to also be used as
a fuel additive to help prevent lead deposits from sticking the
valves, but has become virtually impossible to buy anymore.

[Larryskydives]

You can now buy TCP through Alcor. www.alcorinc.com

[Paul Sengupta]

"Tony Cox" > wrote in message
k.net...
> You'll have to walk me through this Ron, because I still don't
> get it. The flight to warm up the oil was just short of an hour.
> I know that burning fuel creates some water & that it'll get into
> the oil. But why am I seeing 'beading' in the old oil, but not the
> fresh stuff? The only thing that can possibly be different is the
> composition of the old oil compared to the new.

When my mechanic does an oil change on my plane, he
disconnects a hose...the first part to run out is pure water.

I don't have a problem with low oil temperatures either.

Paul

[Tony Cox]

"Paul Sengupta" > wrote in message
...
> "Tony Cox" > wrote in message
> k.net...
> > You'll have to walk me through this Ron, because I still don't
> > get it. The flight to warm up the oil was just short of an hour.
> > I know that burning fuel creates some water & that it'll get into
> > the oil. But why am I seeing 'beading' in the old oil, but not the
> > fresh stuff? The only thing that can possibly be different is the
> > composition of the old oil compared to the new.
>
> When my mechanic does an oil change on my plane, he
> disconnects a hose...the first part to run out is pure water.
>
> I don't have a problem with low oil temperatures either.

Interesting. How much water? Do you specialize in short
trips? Live in a humid part of the world?

[Paul Sengupta]

"Tony Cox" > wrote in message
ink.net...
> "Paul Sengupta" > wrote in message
> > When my mechanic does an oil change on my plane, he
> > disconnects a hose...the first part to run out is pure water.
> >
> > I don't have a problem with low oil temperatures either.
>
> Interesting. How much water? Do you specialize in short
> trips? Live in a humid part of the world?

Mmm, humid part of the world...the UK...but not near the coast.
Think it's more to do with the water generated in the burning than
that from the atmosphere.

Short trips. Usually 1-2 hours. Some of half an hour/40 minutes.

How much water? Um, not sure, but enough it see it pouring out
of the hose clear before the oil starts coming out.

Paul

[Dan Thomas]

"Paul Sengupta" > wrote in message >...
> "Tony Cox" > wrote in message
> ink.net...
> > "Paul Sengupta" > wrote in message
> > > When my mechanic does an oil change on my plane, he
> > > disconnects a hose...the first part to run out is pure water.
> > >
> > > I don't have a problem with low oil temperatures either.
> >
> > Interesting. How much water? Do you specialize in short
> > trips? Live in a humid part of the world?
>
> Mmm, humid part of the world...the UK...but not near the coast.
> Think it's more to do with the water generated in the burning than
> that from the atmosphere.
>
> Short trips. Usually 1-2 hours. Some of half an hour/40 minutes.
>
> How much water? Um, not sure, but enough it see it pouring out
> of the hose clear before the oil starts coming out.
>
> Paul

You don't need to live in a humid part of the world to find water
in your crankcase. Water is a byproduct of combustion, and there are
always a small amount of gases escaping past the piston rings into the
crankcase. Colder weather will cause more of the vapour to condense in
the case instead of travelling through and out of the breather, as the
crankcase is cooler. Short flights or ground runs are much worse; the
oil doesn't get warm enough to boil off the accumulated moisture. If
this moisture is allowed to remain in the oil, it will react with
sulfur and chlorine compounds in the oil and produce acids which eat
the engine away from the inside. Your airplane ages even if it's not
flown.
The original poster probably saw water beading on the upper part
of the dipstick where the tube is in colder air and the vapour will
condense and stay for some time. He likely doesn't normally check his
dipstick after flights and hasn't seen this before. I've seen it
numerous times before changing oil, even after considerable flight
time. Cooler weather is the problem.

Dan

[Tony Cox]

"Dan Thomas" > wrote in message
om...
>
> The original poster probably saw water beading on the upper part
> of the dipstick where the tube is in colder air and the vapour will
> condense and stay for some time. He likely doesn't normally check his
> dipstick after flights and hasn't seen this before. I've seen it
> numerous times before changing oil, even after considerable flight
> time. Cooler weather is the problem.
>
> Dan

Well, being the original poster, I *do* check the dipstick after
each flight, and this particular flight (just before oil change) and the
one before it showed 'beading' where there normally isn't any.
Further, after the oil change, flight, and further check, things were
back to normal, with the oil properly covering the dipstick.

It is conceivable that the beading could be due to an accumulation
of water over the 4 months since the oil change. I discount this
because the flights preceding the checks which revealed beading
were 4.4 and 1.5 hours respectively -- which should have been
sufficient to boil off any absorbed water, at least to the level where
the water content was not significantly different from that in the
'clean' oil after a 1 hour flight.

My gut feeling is that the difference is due to the changing chemical
composition of the oil with age.