Oil Longevity

[Red]

As far as I can find via the huge brain of google unused oil in a container has a recommended storage life of 5 Years.

What say you?

[skippydiesel]

You talking aviation or automotive oil?

 

I believe aviation oil is certified. Certification requires that the oil be sampled periodically(??) to determine that it meets the standard/or not. If its Av oil it will have a date on it.

[Red]

I don't mean tests to ascertain quality before release of sale.

How long in storage after you buy is considered acceptable?

I don't think I've ever seen a use by date.

I'm specifically thinking of a semi synthetic motorcycle type oil as commonly used for Rotax 912 engines but I wonder the same of all modern oil types

 

 

[skippydiesel]

Good question.

 

Speculation: The oil should be good for long term ( guess  @ 5 years ??) storage & subsequent use, if stored in an airtight container, full or almost so, away from extremes of temperature.

 

".....ascertain quality before release of sale." The fact that such tests are required for Av oils would suggest to me that some deterioration , in storage, is possible/likly (?)

 

Depending on the value/importance of the engine, I often use oils, leftover from previous services, without any apparent ill effect - talking mowers/pumps paddock basher, etc not aircraft or my road vehicle.

 

Strange that some knowledgeable Forum person hasn't answered your question.

[spacesailor]

Most " service ' garages buy oil in large bulk drums.

And are seldom sealed or even have the ' bung ' replaced once opened .

Supposedly , our oil " should " be changed for " Summer & Winter " .

Does anyone check their ' service centre ' for your annual oil-change compliance .

spacesailor

[skippydiesel]

Supposedly , our oil " should " be changed for " Summer & Winter " .

 

I think this practise has largely been made redundant (in relativly temperate climates) by  multigrades oils.

[facthunter]

I'd be a bit concerned if it was over 3 years old for use in a plane. Synthetic should be more stable. OLDER  synthetics may use different bases.  Like ESTERS. .  Rare these days but you can't assume compatibility. IF you use oils that do mix the lowest performing one is the one you judge the mix by..  I would never flush a motor with so called flushing oil.   Too risky for things like cam lobes and followers. Nev

[Red]

1 hour ago, facthunter said:

I'd be a bit concerned if it was over 3 years old for use in a plane. Synthetic should be more stable. OLDER  synthetics may use different bases.  Like ESTERS. .  Rare these days but you can't assume compatibility. IF you use oils that do mix the lowest performing one is the one you judge the mix by..  I would never flush a motor with so called flushing oil.   Too risky for things like cam lobes and followers. Nev

3 years feels about right to me though with no empirical backing to that figure.

Question was prompted by my recent change of aeroplane which came with a couple of 5 litre cans of oil that are likely around that age, I think I'll use a little if I need small top up in the near future and consign the remainder to various garden machinery 

interesting take on flushing oil, something i've never used and assume its only to be used on something left standing with sludge build up and I guess must contain solvants

 

[facthunter]

If it's got sludge, strip it, and clean it properly.  Moving sludge runs a risk of blocking up oilways. .  Nev

[skippydiesel]

Ah hhh! "Flushing Oil" - The memories that little phrase brings back -magic in a can. I still have a container of it gathering dust on a shelf somewhere.

 

A redundant concept now, with the almost universal use of high detergent engine oils.

[facthunter]

There's a lot of oil splashing about in a modern engine and they warm up quicker . IF the motor runs too cold it'll wear out much quicker Motors running on LPG run very  clean but you should still change oil once a year at least to reduce acid  that will  dissolve the lead in copper lead bearings. Alutin  is getting more common and needs good filtration as it doesn't like dirt.  Short runs and /or dusty conditions change more often. Nev

[onetrack]

Lubricating oil is a base crude with a substantial number of chemical additives added to it. All those chemical additives are not stable for the long term, they're designed and formulated to react with undesirable by-products of combustion, deal with major temperature changes, and deal with humidity.

In addition, a number of the additives consist of heavier particles, such as graphite and molybdenum disulphide flakes, designed to stay in suspension for some reasonable length of time, but they will eventually sink to the bottom of the oil container after some years.

Sealed oil containers usually have a recommended use-by period of 4 to 5 years, according to the oil companies. Once opened, the storage period would be reduced, as the container then has increased air space in it, and introduced contaminants such as moisture, via the air entering the container.

Then there's the potential reaction between the oil and the container it's in. I'd imagine oil in metal containers would not be in pristine condition after 5 years, thanks to potential chemical reactions between the metal of the can or its coating, and the oil additives. I'd have to opine plastic or polyethylene containers would pose far less risk of chemical interactions with the oil.

But the oil companies play it safe, and they have to cover their a$$$$'s against damage claims, so they set a reasonable time limit on storage, which is likely to be based on the length of time that they consider the additives are still capable of doing their job.

There's an interesting and comprehensive article below that discusses oils and their additives. 

 

Lubricant and Lubricant Additives | IntechOpen

WWW.INTECHOPEN.COM

---

Lubricants have been used by humans for thousands of years in their simple machines such as wheel-axle bearings and sledges. Modern machines are much more complicated and are composed of many...

 

[Red]

Cheers Onetrack, I'll have a read of that.

These modern Oils are quite amazing but I don't think they're ever gonna smell as good as Castrol R💥

[planedriver]

That SMELL comment certainly brings back a few memories.

[facthunter]

Speedway bikes make your workshop smell nice for ages. I always shake oil containers before pouring from them

[BrendAn]

Look at this crap my jab spits out.

It doesn't use much oil at all but must make plenty of condensation.

[Red]

Gordon Bennett!!! what oil temperature do you run at?

Or is this a joke?

[BrendAn]

1 hour ago, Red said:

Gordon Bennett!!! what oil temperature do you run at?

Or is this a joke?

90c

[Red]

A nice temperature then.

Is this coming from the breather after the catch tank?, I guess if its very high humidity and there is no sign of the same high water contamination at the dipstick then its not too much or a worry and could be forming in the catch tank.

Knowing how prone to bore corrosion the jabs are (unless its a gen 4) then Id want to get to the bottom of it.

 

P.S. I've never had anything near that bad spat out by my Jab or any other air cooled  engine

Edited June 25 by Red

[skippydiesel]

Rotax recomend oil temps reach above 100C  for a sustained period, specifically to drive of water & other volatile contaminants. I aim for mid to high 90C in Cruise and hope to see over 100C during climb out.

 

90C is far to low.

[Red]

90C is a good operating temp for a Jab on an XAir, the engine is exposed and the sensor will be under reading actual temperature

[skippydiesel]

25 minutes ago, Red said:

90C is a good operating temp for a Jab on an XAir, the engine is exposed and the sensor will be under reading actual temperature

Not if you get calf scour (water/oil emulsions) coming out of the crankcase breather. Something needs to be done to raise the oil temp. It's quite likly that the inside of that engine is coated in a thick film of "gunk" - Leave it long enough and it will reduce the flow of oil through distribution galleries.

[BrendAn]

2 hours ago, Red said:

A nice temperature then.

Is this coming from the breather after the catch tank?, I guess if its very high humidity and there is no sign of the same high water contamination at the dipstick then its not too much or a worry and could be forming in the catch tank.

Knowing how prone to bore corrosion the jabs are (unless its a gen 4) then Id want to get to the bottom of it.

 

P.S. I've never had anything near that bad spat out by my Jab or any other air cooled  engine

oil in the engine is spotless. it only makes this emulsion after more than an hours flying. i run it weekly because number 2 may have a bit of pitting. 80/60 which is the bottom limit for a 2200 leakdown but still serviceable. the other 3 are 80/70.

[BrendAn]

1 hour ago, skippydiesel said:

Not if you get calf scour (water/oil emulsions) coming out of the crankcase breather. Something needs to be done to raise the oil temp. It's quite likly that the inside of that engine is coated in a thick film of "gunk" - Leave it long enough and it will reduce the flow of oil through distribution galleries.

its not in the engine. oil is perfect and it hardly uses any.  it used to have an oil cooler that was a lot bigger than the one on it now.

[BrendAn]

pretty sure the manual said 90 was good .