How long does an oil film stay on engine parts after shutdown

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So, as I thought, most people agree that an oil film will stay on the engine parts for years if not forever. I am wondering then why a small engine that I have seized hard in place after 5+ years of non use. I can't get the thing to move. Now I make it a practice to turn my model engines over by hand several times yearly. So the same thing can happen on a full size car engine? If an oil film remains on the engine how can it seize up?
RC engines running glow fuel (castor oil + nitro) are different. When I flew RC airplanes that run glow fuel, I found they would gum up if I didn't flush them. At the end of each day I would cycle ATF through the engine. This worked well: stopped them from gumming up, prevented corrosion and over years of use didn't seem to have any negative effects.

Why don't aircraft engine oils use some of the beneficial additives that PCMOs have?
They require "ashless dispersant", and ashless means no Calcium or similar elements. For more on aviation related lubrication, Mike Busch is a great reference, like this. For your specific question, jump to 47:40.
 
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I like intelligent molecules and currently using it in one of my older cars. this car has a $4/qt budget for oil. I may reduce the budget for this car to ST or Kirkland levels but Castrol GTX Magnatec Full Synthetic 10W30 has a 6.1 Noack that not many can beat or match. Not even fancy oils.
Unintelligent molecules do as they're told.

No need for oil to think for itself.

Here are two "fancy" 10w30s that spank intelligent molecules' NOACK numbers.

Amsoil 10w30 ATM with a NOACK of 4.1
Amsoil 10w30 ZRT with a NOACK of 5.5 (these particular molecules seem to be targeted towards infrequently driven vehicles).
 
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One year I opened up my motorcycle engine that had been sitting all winter, in the spring and it still had a film of oil on the cam lobes.
I was using 10w-40 during the riding season.
It had been sitting for 6 months of non use.

Made me want to use it in our cars. 10w-40.
 

OVERKILL

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Unintelligent molecules do as they're told.

No need for oil to think for itself.

Here are two "fancy" 10w30s that spank intelligent molecules' NOACK numbers.

Amsoil 10w30 ATM with a NOACK of 4.1
Amsoil 10w30 ZRT with a NOACK of 5.5 (these particular molecules seem to be targeted towards infrequently driven vehicles).
Castrol's marketing works apparently 🤷‍♂️

1620244055033.jpg
 
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And Noack is irrelevant to film formation at normal ambient temperature. Even if it wasn’t it’s the larger hydrocarbon molecules that remain on the surfaces.
There's a reason oil specs state a maximum NOACK value.

How could a lower value than the approved maximum be detrimental?

You, of all people, should realize that.
 
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There's a reason oil specs state a maximum NOACK value.

How could a lower value than the approved maximum be detrimental?

You, of all people, should realize that.
Where did I ever say a lower Noack value is detrimental? I have said in the past that Noack is a relatively useless performance parameter much like flash point and pour point. But I've never said that lower is bad.
 
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Where did I ever say a lower Noack value is detrimental? I have said in the past that Noack is a relatively useless performance specification much like flash point and pour point. But I've never said that lower is bad.
6 of 12, half of a dozen.

All aside from the flash/fire points that are meant for first responders, but that's irrelevant to the light hearted banter between OilUzer & me regarding NOACK values.

Appears that we're somewhat in sync here.

We best buddys finally?
 
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SR5

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Oils of yesteryear were thicker, which helps them stick to engine parts longer before drooling off due to gravity.
Just to add, apart from the modern Group V esters and such, the old Group I oils, while less oxidatively stable were more polar than modern Group II - III - IV oils and so would have attached themselves better to the metal surfaces of the engine.

If they only metric of concern was oil drain down of a sitting engine, then I would select an old school thick Group I 20W50 mineral over a modern Group III 0W20 synthetic any day of the week.

However, we are not forced to make such black or whites decisions, hence my use of synthetic Magnatec 5W30 with designer polar molecules added.

BTW did anybody notice the Magnatec 15W40 semi-synthetic (API SN/CF, ACEA A3/B4) in the previous list of Magnatec flavours available in Australia? Given the standard limitations of cold starting ability in cold climates, that would be my pick.
 
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Unintelligent molecules do as they're told.

No need for oil to think for itself.

Here are two "fancy" 10w30s that spank intelligent molecules' NOACK numbers.

Amsoil 10w30 ATM with a NOACK of 4.1
Amsoil 10w30 ZRT with a NOACK of 5.5 (these particular molecules seem to be targeted towards infrequently driven vehicles).

Amsoil SS 10W-30 is one of my favorite oils with 4.1 Noack and LOTS of moly. If I didn't put a price limit (budget) for engine oil, I would always use this oil. Have never bought it at least not yet.

However, Amsoil is about $12 /qt.

Castrol GTX Magnatec Full Syn 10W30 is under $4 /qt. with 6.1 Noack.

Now beat that Noack with any "fancy" oil.

My bad. It's the internet and I should have said considering the price.
 
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Btw, some of you guys are good at dissecting a post and taking things out of context ...

Noack was just some thing that came up during discussion while we were talking about something else ... It happens you know when people are talking so don't try to overanalyze things.

I've had several posts in the past regarding Amsoil SS 10W30 low Noack numbers so I am fully aware of Noack numbers as it is one of the things I pay attention to when I select an oil.
 
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^^^ Lower Noack is better than not IMO when it comes to hot areas of the engine were it can get pretty hot and "vaporize" easier (ie, ring pack, underside of piston crowns, journal bearings), so it's a parameter I also look for. There's a reason there is a Noack limit oils must meet in order to be certified.
 
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In the context of a persistent oil film over long periods of non-operation Noack has little to no relevance. If you look back that was the context of my response.
 
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Of course, never said anything associated with oil film... just sayin' since we're on Noack. :)
 
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Amsoil SS 10W-30 is one of my favorite oils with 4.1 Noack and LOTS of moly. If I didn't put a price limit (budget) for engine oil, I would always use this oil. Have never bought it at least not yet.

However, Amsoil is about $12 /qt.

Castrol GTX Magnatec Full Syn 10W30 is under $4 /qt. with 6.1 Noack.

Now beat that Noack with any "fancy" oil.

My bad. It's the internet and I should have said considering the price.

Amsoil 10w30 OET - NOACK 5.2
Amsoil 10w30 ADN - NOACK 4.5

Both around $5 a quart, and a bit cheaper by the case/gallon, if I recall correctly.
 
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Amsoil 10w30 OET - NOACK 5.2
Amsoil 10w30 ADN - NOACK 4.5

Both around $5 a quart, and a bit cheaper by the case/gallon, if I recall correctly.

I don't recall anything below $8 or $9 per quart last time I was on their website. Its been a while, i will check again.
 
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You make a valid point.
I checked the prices - $5.45 for OET with my Politically Correct pricing.
 
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