Mixing oils?

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BabaYaga

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Just a quick check: I am planning the annual oil and filter change in the Beta engine. The oil left over from last year will not be quite sufficient in volume, but I have some left from earlier years, although not the same brands.
Could I safely mix these? They are all 15W40 and all carry designations as ASEA E7 and API CI-4.
Would be grateful for advice from someone knowledgable.
 
BabaYaga said:
Just a quick check: I am planning the annual oil and filter change in the Beta engine. The oil left over from last year will not be quite sufficient in volume, but I have some left from earlier years, although not the same brands.
Could I safely mix these? They are all 15W40 and all carry designations as ASEA E7 and API CI-4.
Would be grateful for advice from someone knowledgable.
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If they are the same grade and specification they will be fine to mix. They do not have to be the same brand.
 
CI-4:
Introduced in 2002. For high-speed, four-stroke engines designed to meet 2004 exhaust emission standards
implemented in 2002. CI-4 oils are formulated to sustain engine durability where exhaust gas recirculation
(EGR) is used and are intended for use with diesel fuels ranging in sulfur content up to 0.5% weight. Can
be used in place of CD, CE, CF-4, CG-4, and CH-4 oils. Some CI-4 oils may also qualify for the CI-4 PLUS
designation.
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from: http://www.apicj-4.org/2009_ENGINE_OIL_GUIDE.pdf

E7:
ACEA E7 Stable, stay-in-grade oil providing effective control with respect to piston cleanliness and bore polishing. It further provides excellent wear control, soot handling and lubricant stability. It is recommended for highly rated diesel engines meeting Euro I, Euro II, Euro III, Euro IV and Euro V emission requirements and running under severe conditions, e.g. extended oil drain intervals according to the manufacturer's recommendations. It is suitable for engines without particulate filters, and for most EGR engines and most engines fitted with SCR NOx reduction systems. However, recommendations may differ between engine manufacturers so Driver Manuals and/or Dealers shall be consulted if in doubt.
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from: https://www.oilspecifications.org/acea.php

No information about compatibility from those specifications, just recommended duty and characteristics.

Check the containers for other information such as synthetic/mineral. If all else is equal the mix away.
 
Thank you both. Oils are certainly all mineral. I am a bit unsure how ’grade’ is determined, other than the designations mentioned. Suppose I will be fine mixing, though.
 
BabaYaga said:
Thank you both. Oils are certainly all mineral. I am a bit unsure how ’grade’ is determined, other than the designations mentioned. Suppose I will be fine mixing, though.
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Indeed. You can mix any engine oil with any other engine oil. Mineral, synthetic, thin, thick ... it doesn't matter.

The only consideration is whether you know what the properties of the final mixture are going to be. If you mix two oils with the same viscosity range, for example two oils of spec. 15W-40, you will end up with a 15W-40 mixture. However, the further apart in specs the two oils are, the more difficult it will be to guess the properties of the mixture and therefore the more unwise it would be to assume that it will be correct for your engine.

Richard
 
Engine oil specifications include the clause that they be miscible with similar oils of other manufacturers. Laboratories will test for this using 10:90, 50:50 and 90:10 mixtures of the test oil and several others. I have experience of mixes of non-engine oil where an additive in one reacted with an additive in another, causing serious mechanical seal problems. This might be a problem in heavily additived oils such as gear oils, hydraulic fluids and ATFs.
 
bowlsboat said:
I expect you already know that Beta engines (well my 28hp at least) should not have synthetic oil as it adversely affects the oil seals.

Eric.
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As per the other thread: http://www.ybw.com/forums/showthread.php?509232-engine-oil-modern-equivalent-of-CD-standard there is no scientific evidence that any additional oil seal wear is caused by synthetic oils. What is understood is that synthetic oils are usually used in lower viscosity formulations than mineral oils and that, if seal are already worn, then synthetic oil will reveal that wear sooner. However, the wear already exists and it will be revealed by a mineral oil in due course.

I switched to using Mobil 1 fully synthetic oil without any problems in the late 1970's and that was in a Vauxhall engine designed in the 1960's. :)

Richard
 
BabaYaga said:
Just a quick check: I am planning the annual oil and filter change in the Beta engine. The oil left over from last year will not be quite sufficient in volume, but I have some left from earlier years, although not the same brands.
Could I safely mix these? They are all 15W40 and all carry designations as ASEA E7 and API CI-4.
Would be grateful for advice from someone knowledgable.
Click to expand...

Sounds like you are only a small amount short of the oil from last year to meet the quantity. Why not buy that small quantity to make it up.
Why risk mixing the oils if you're in any doubt.
 
sailorman said:
there really will not be a risk in blending the oil
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I do tend to agree with you but if it were my engine I would just get some more of the same oil for the amount it costs.
I am not saying this from a technical knowledge backgound, I'm just someone who likes peace of mind.
 
Thanks again for your replies. The mixed oil is now in the engine. Turned out that the two different left overs I had from four and five years ago combined made up the 3 litres needed.
As mentioned they are both mineral type and both carry the designations as per my first post.
Should also say that my annual hours are very low...
 
My boat I’m very particular with the oil, but my Passat, I shove any vaguely oily substance in it and never have any probs. Well not in the last 12 years anyway.
 
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