Mobil 1 FS 5w50 Vs 0w40 Euro?

[John9721]

Good morning BITOG, I wanted to inquire about something that sparked in my head during a period of no sleep last night, lol. Currently in my MK7 GLI I use Mobil’s 0w40 Euro. The car calls for a 0w20, but between recommendations from the tuner, as well as running E85 a majority of the time on this car I opted for the thicker oil.

Until last night I wasn’t aware that the 5w50 variant was also a Euro oil, and while it doesn’t meet any VW specs it still carries Porsche A40.

As much as I’m sure this is an overkill scenario, I wondered if running the 5w50, especially going into summer, combined with E85 would be a smart choice? I’ve read for years that Mobil’s oils can be on the “thinner” side of their rating, which has me wondering if a 50w, which would likely sheer to a 40w at temp, would beneficial. OCI’s are typically 4-5k, at most.

 

[JavierH19]

Most likely fine with off the shelf 40's. You could try Mobil 1 15w-50 in this warm weather too. Although it doesn't have euro approvals it's very well formulated and lspi safe. I don't think i'd do 4-5k miles with e85 being used regularly and with a tune on it. I wonder what the tan of the oil would be.

 

[shortyb]

Are you tuned for E85 or a blend like E30? If running straight E85, I wouldn't be running ANY oil 4-5K, much less Mobil 1 0W-40. With the typical VW dilution and the ethanol, your oil will be a mess by 5K. IF you ARE tuned for straight E85, then use the Mobil 1 5W-50 and UOA it at 3K with a decent analysis company that does fuel dilution by GC.

 

[chris719]

X2 5W-50 has the same additive package as the FS 0W-40 and could even be mixed in proportion, I was told that by an XOM program lead. But yes, you can run the 5W-50 for sure. Since it has that same additive package it will functionally be 502/505.

 

[UNC063]

Did run the Mobil 1 5w-50 in my land cruiser. Engine did run pretty quiet with that oil

 

[BMWTurboDzl]

Have you had a used oil analysis done to see what level of fuel dilution you're seeing? Personally I would want to use a narrower spread like a 5w-40 with E85.

 

[John9721]

Have you had a used oil analysis done to see what level of fuel dilution you're seeing? Personally I would want to use a narrower spread like a 5w-40 with E85.

What would be your reasoning for 5w40 over a 0w40/5w50?

 

[chris719]

What would be your reasoning for 5w40 over a 0w40/5w50?

Probably that it could imply a thicker base oil and less VII contribution to the finished viscosity. It's generally true but varies from product to product. Personally I'd have zero reservations about either the Mobil 1 5W-50 or, say, Pennzoil Platinum Euro 5W-40. I'm not sure there's much in it.

 

[fantastic]

What would be your reasoning for 5w40 over a 0w40/5w50?

If you're going somewhat shorter intervals it would work well. However, a wide viscosity spread like that 5w-50 could shear down quite quickly. If using it for longer intervals you may be no better off than a 40 grade at that point. I'd certainly try both to see where the viscosity landed & where it may make sense to use one vs the other or when to change the 50 grade depending on your use.

I see your interval mentioned now. Try the 50 grade you want to use. I think it could very well give you all the protection you need for your engine.

 

[chris719]

If you're going somewhat shorter intervals it would work well. However, a wide viscosity spread like that 5w-50 could shear down quite quickly. If using it for longer intervals you may be no better off than a 40 grade at that point. I'd certainly try both to see where the viscosity landed & where it may make sense to use one vs the other or when to change the 50 grade depending on your use.

I see your interval mentioned now. Try the 50 grade you want to use. I think it could very well give you all the protection you need for your engine.

In the testing LSJ did, the 50 loses more by percentage but still ends up quite a bit higher than the Castrol 5W-40 and the Mobil 1 0W-40 in HTHS after the KRL.

 

[fantastic]

In the testing LSJ did, the 50 loses more by percentage but still ends up quite a bit higher than the Castrol 5W-40 and the Mobil 1 0W-40 in HTHS after the KRL.

Thanks for that & I'm all for thicker grades.
I usually rebuttal some that say "Start w/a lower grade b/c the higher grade will shear" (I sound like I'm saying that above though) but many times I've seen the higher oil grade handle plenty of more mileage before it shears to the lower grade range. I believe I remember that comparison, I think that's when he tested the other Euro 40's too. Only negative I can think of is that my Walmart doesn't stock it like the Euro 40 grades.

 

[rollins.]

Cannot find the exact thread but I think this was the pic :

 

[OVERKILL]

Cannot find the exact thread but I think this was the pic :

View attachment 329635

Underscoring that a 0W-40 is not in fact less shear stable than a 5W-40, as many often postulate.

 

[chris719]

Underscoring that a 0W-40 is not in fact less shear stable than a 5W-40, as many often postulate.

Yeah, if all other formulation variables are held constant, it would be most of the time, but that's not true as we see here. The 5W-40s are the "budget" Euro oils for Mobil and Castrol vs the more premium targeted 0W-40.

 

[scrllock]

Good morning BITOG, I wanted to inquire about something that sparked in my head during a period of no sleep last night, lol. Currently in my MK7 GLI I use Mobil’s 0w40 Euro. The car calls for a 0w20, but between recommendations from the tuner, as well as running E85 a majority of the time on this car I opted for the thicker oil.

Until last night I wasn’t aware that the 5w50 variant was also a Euro oil, and while it doesn’t meet any VW specs it still carries Porsche A40.

As much as I’m sure this is an overkill scenario, I wondered if running the 5w50, especially going into summer, combined with E85 would be a smart choice? I’ve read for years that Mobil’s oils can be on the “thinner” side of their rating, which has me wondering if a 50w, which would likely sheer to a 40w at temp, would beneficial. OCI’s are typically 4-5k, at most.

I've seen 600-700hp EA888s on E85 and nothing but 0w40 FS torn down or scoped and look absolutely pristine. Take advantage of the current pricing, change it often, keep it topped off and it's not an issue. There are certainly other oils that will do the same thing but the main thing you can do to deal with E85 is change the oil more often. Absolutely nothing wrong with the 5w50, viscosity is great, but you still want to keep an eye on TAN, and with the OCIs I like for e85 (2000-2500 miles), the cheaper 0w40 wins out for me.

 

[Japanese]

Just for the record - Mobil 1 FS Euro 5W-50 was the factory fill for Lexus LFA. Engine was V10, 12:1 compression ration revving to 9,000 RPM.

As stated on the PDS on the Mobil site as well.
Mobil 1™ FS European Car Formula

 

[Tifosi]

Q: FS 0W-40 was reformulated ~1 or 2 years ago, did the FS 5W-50 get reformulated as well? Thanks.

 

[chris719]

Q: FS 0W-40 was reformulated ~1 or 2 years ago, did the FS 5W-50 get reformulated as well? Thanks.

It's the same additive package as the 40.

 

[Tifosi]

It's the same additive package as the 40.

What about the base oil? I recall reading somewhere that FS 0W-40 is reformulated with Group 3 base oil, or has it always been Group 3?

 

[tired]

What about the base oil? I recall reading somewhere that FS 0W-40 is reformulated with Group 3 base oil, or has it always been Group 3?

They removed the esters after API SN I believe, but it still meets the same approvals.