Mixing Mobil 1 ESP X2 0w20 and ESP 0w30

Messages
142
Location
Colorado
Before I get jumped on about warranty, I've always advised staying with the spec so you don't have warranty problems. What is making me reconsider this is the last UOA I did, I had considerable fuel dilution in my Audi SQ5. Probably winter related, but it concerned me a bit. I'm trying to find a happy compromise of engine protection and warranty protection. I'm betting a mix of the two would still have enough UV die to pass inspection.

So on to the oils themselves. A lot of my research is from the results for both oils at https://www.ato24.de/ and some VOA here.

TBN: same
Noack: similar, 0w30 slightly better
AW: both have similar high amounts of moly and boron

Viscosity related measures are different obviously but is it safe to say the end product would be the weighted average of the two? Even for the cold pumpability test where the 0w20 is 4000 and 0w30 is 6000, so a 50/50 mix should be 5000? The chemistry of the add pack itself is probably identical? If I mix just enough to get 3.1-3.2 HTHS, it appears to me there would be no issues?
 
Messages
8,780
Location
North Carolina
Just pick one and run it. You either feel 0W-30 will protect better and spare you warranty work, or you feel the 0W-20 is good enough that the car is warrantied with it.

Mixing both seems silly and a half measure.
 
Messages
1,026
Location
Upper midwest
Jumped on about warranty? Huh.... You probably can count on one persons hands and toes on any dealership in the USA that is going to send out for a UOA on a toasted motor if it is full of oil, the engine in not sludged up, the engine oil is not red, it appears to be the correct viscosity, and it doesn't smell like gear oil.
 
Last edited:
Messages
8,780
Location
North Carolina
Jumped on about warranty? Huh.... You probably can count on one persons hands and toes on any dealership in the USA that is going to send out for a UOA on a tosted motor if it is full of oil, the engine in not sludged up, the engine oil is not red, it appears to be the correct viscosity, and it doesn't smell like gear oil.
Well if any marque was going to explore it, it would probably be Audi.
 
Messages
2,393
Location
Paradise of Florida
508 dyed a pretty color and has a chemical tracer

0w30 should be fine. If there is an engine failure, I would tow home and drain enough oil to top off with dye and chem from 508.

I'd doubt there would be issues if you ran a full dose of 5w40. So, the 0w30 or 50:50 isnt an issue.

Shorten your OCI if you have dilution. The 10k interval is great for a lease or short term ownership.
 
Messages
1,026
Location
Upper midwest
Well if any marque was going to explore it, it would probably be Audi.
Nope, I have a nephew who works at the largest Audi dealership in Minnesota and one that works at the the largest Lexus dealership in Minnesota. Both have been at their dealerships for over 10 years. I have brought up this issue and both are the ones who gave me this scenario they both go by.

The engine must be full or 1 Qt down ++ of oil, the engine in not sludged up, the engine oil is not red, it appears to be the correct viscosity, and it doesn't smell like gear oil.

Both have NEVER heard of sending out for a UOA unless they find "weird" oil in it. (IE gear oil or ATF) if it passes the above they get a new motor.
 
Last edited:
Messages
1,026
Location
Upper midwest
Most of their tanked engines are from lack of oil, owners with oil drinkers that don't catch their lowering oil level or a change of personality of a non drinker going to an oil drinker and they don't catch it in time. Or in Audi/VW case someone with a wild tune and Audi/VW has pretty good automated tune sniffing anti-tuneware. Both Audi/VW and Lexus has pretty robust engines, unlike Hyundai/Kia.
 

BrandonT

Thread starter
Messages
142
Location
Colorado
IIRC over the 5% test limit, so unknown just how high. The viscosity was actually a bit over VOA, I assume due to oxidation. This was with the Castrol oil. I've now switched to Mobil 1 ESP X2 and will check again soon. OCI @9k, but I may back off that a bit depending on the results.
 
Messages
12,599
Location
Colorado Springs
That engine will take anything VW504.00/507.00 or VW511.00. Grade wise do not worry.
long time ago here it was discussed that mixing two oils will not results in some 50/50 mixture. It doesn’t work that way.
so, stick to one grade.
 

BrandonT

Thread starter
Messages
142
Location
Colorado
If you have a link to that discussion I would like to read it. I suppose I could mix and it send if off for a VOA and see what comes back.
 
Messages
12,599
Location
Colorado Springs
If you have a link to that discussion I would like to read it. I suppose I could mix and it send if off for a VOA and see what comes back.
It doesn’t work that way. You cannot mix 0W20 and 0W40 and get 0W30. It is not working that way. You can Google it here and you will stumble upon it. If you are concerned with warranty, stick to 0W20. I personally would not, and I would use VW504.00/507.00.
does your manual gives any other options?
 
Messages
8,780
Location
North Carolina
Nope, I have a nephew who works at the largest Audi dealership in Minnesota and one that works at the the largest Lexus dealership in Minnesota. Both have been at their dealerships for over 10 years. I have brought up this issue and both are the ones who gave me this scenario they both go by.

The engine must be full or 1 Qt down ++ of oil, the engine in not sludged up, the engine oil is not red, it appears to be the correct viscosity, and it doesn't smell like gear oil.

Both have NEVER heard of sending out for a UOA unless they find "weird" oil in it. (IE gear oil or ATF) if it passes the above they get a new motor.
Don't "nope" me.

The oil has a marker in it for a reason. If an Audi rep is called out to look over and approve a warranty repair for a lubrication related failure, you can bet he'll at least shine a light over the oil.

Your anecdote is just as relevant as anyone's. The FACT is that 508/509 oil has a UV marker.
 

BrandonT

Thread starter
Messages
142
Location
Colorado
There is nothing magical about hydrocarbon viscosity scaling with molecular weight. It may not be a perfectly straight line but it is close. The only hitch is the viscosity improvers, but even there it can't be radically non-linear.
 
Messages
32
Location
Wyoming
Honestly I've been registered on bobistheoilguy for years I suppose, but just never think to "stop by" and see what's happening.

I'm enjoying this discussion, and can offer a couple of weblinks that you all may or may not appreciate, but I found them quite informative.
Also, right up front, please don't beat me up unnecessarily, I am not an Audi owner and certainly know nothing about any possible risks you may encounter if you deviate from any exacting specifications of oil in your application. The bottom-line basic facts of motor oil engineering is not "vehicle brand specific." However, yes it is true we all must be sure to comply with the specific manufacture's absolute requirements. (In my case the absolute requirement is GM Dexos 1 Gen 2.) -sorry, I'm not yelling, just emphasizing key points-

To "BrandonT", I offer this: After one of my last UO analysis reports, I was rather unhappy with the viscosity at 100c being substantially lower that what I'm comfortable with. And similar to your results, my report did show a "trace" of fuel, but nowhere near the "allowable" limit. I now suspect it may be directly related to molecular "shearing" of the "long chain" viscosity improver additive.

That set me off on many hours of research (and posting a question on another forum) as to whether or not a 0W30 oil would be better than 0W20. -seems to me it would still give me the same winter temp/cold start protection, but the bonus should be significantly better high temp protection, and hopefully better wear protection. -and BTW, I have still not decided what I'm going to do. I still have a lot of warranty left, which I'd rather not risk. However, I seriously doubt using 0W30 vs the 0W20 would even be detectable in my case. (non-Audi, sorry, but the same motor oil-related engineering principles apply,,,)

So the first weblink deals with high temp high shear Standard ASTM D-4683 and other standards including SAE J-300, and many other ASTM D xxxx x standards. With two apologies: One, the dissertation is quite lengthy, and two it is from a Corvette owner, which I hope is not "fighting words" for you, or will be unnecessarily painful otherwise. Personally, for my needs, I found the last several paragraphs to be the most valuable. https://www.corvetteforum.com/forums/c5-tech/4496042-engine-oil-shearing-and-specs-explained.html

With appropriate apology, the second link is to a specific motor oil manufacturer's site, but the dissertation does a good job of explaining the factual basics of base stocks and additives. It certainly makes obvious the extreme advantage of a "Group IV" base stocks. A key statement in that article is that some synthetic base stock oils (Poly Alpha Olefins – PAOs and Esters) have such high natural Viscosity Indices that little if any additives are needed to achieve the multi-grade finished product. That link is: https://thelubepage.com/amsoil-maga...m-and-synthetic-oil-base-stocks-and-additives

Hey, I hope you all find the above informative, and hopefully even useful.

Okay, one last thing: Oil Film Strength. This is likely an extremely important (maybe the most important?) factor in the interest of good engine wear protection for all motor oils. And by that, I mean the specific value measured in pounds per square inch at which any specific motor oil fails. And that can only be determined with very specific laboratory equipment using exact controlled standards by an "independent party." (BTW, I can offer a link to one of those too, if anyone is interested,,,)

I just LOVE the following statement of basic lubrication fact:
"In any lubricated assembly employing two metal surfaces, there will not exist any wear of those surfaces as long as the surfaces never physically contact each other. Specifically when a sufficient boundary layer of lubricating fluid is continuously maintained, there is no foreign particle present larger than the clearance between the parts, AND that boundary layer has a film strength which exceeds the highest mechanical force attempting to make the two metal surfaces contact each other."

And of course, in the case of automotive engine oil, many other factors are important too. Like all of the important additives, like detergents, anti-corrosives, dispersants, acid neutralizers, anti-wear, etc. etc.

At this point for me, I am going to seriously consider using a synthetic oil with Group IV base stock. -and at this point, I'm only aware of a few brands. Also, I believe a 0W30 very obviously provides better protection at normal operating (hot) oil temperatures. AND, of course, it always goes without saying, using a correct high quality oil filter, and changing the oil religiously.

Cheers Everyone !!
 
Messages
32
Location
Wyoming
Just discovered this excellent dissertation (A Review of Mineral and Synthetic Base Oils) right here on the BITOG site.
I just had not thought to click on the "home" button before.
I could have saved a lot of time and typing (above),,,
 
Top