Mobil Drive Clean 5W-30 Shearing out of grade

[Tim_Siford]

Curious if anyone else might be experiencing the same thing ... or else to warn others about the phenomena.

New 2005 Subaru Impreza WRX STi (2.5L turbocharged flat 4 boxer, rated at 300/300). No modifications.

1) I changed the oil at 394 from the factory fill to Mobil Drive Clean 5W-30. I should have sent a sample in to blackstone of the factory fill ... oooops, I didn't.
2) Changed oil again at 1164 miles. With only 770 miles on a fill of Mobil Drive Clean 5W-30, the viscosity was almost out of grade (54.2 when normal is 54-61).
http://www.bescaredracing.com/sti/oil/analysis/1164.jpg
3) Changed oil again at 2210 miles. With 1046 miles on a fill of Mobil Drive Clean 5W-30, the viscosity was already out of range (52.9 when normal is 54-61)
http://www.bescaredracing.com/sti/oil/analysis/2210.jpg
4) I'll be checking my newest fill of Mobil Drive Clean 5W-30 at ~3000-3500 miles. I was originally going to go to 3500 but with the shearing in the last 2 samples I think I might just pull the oil at 3000 miles and swap to something else.

I was thinking of swapping to Mobil's 5W-30 Blend for a couple oil changes before going to full synthetic. However, with this shearing going on I might just hop on over to full M1.

Any thoughts on the shearing or swapping to full synthetic instead of the blend?

 

[JHZR2]

I believe those cars come with M1 synthetic from the factory. Chances are there is a reason why...

my saab turbo wants an A3 rated, GM-LL spec synthetic oil. theres a reason for that, partially because my car can go 15k+ between changes, but also because of oil shearing.

The shear stability of a syn oil is much better than a dino. 5w-30 is a pretty big spread, regardless of how good the VII chemistry gets. I recall many times on here seeing people saying that these subaru turbo engines are pretty tough on the oil.

Either drive light (and it might not help) or go to M1. Id probably have kept M1 in there the whole time. I dont think modern engines have the break in issues when syn oil is used the way older ones apparently did. Look how many high performance cars come with syn from the factory...

JMH

 

[glxpassat]

I would only use a good synthetic with a turbo. From what I've read here, the two most shear stable for the money are German Castrol 0w-30 or Mobil Truck & SUV 5w-40. If you have to run dino, stick to a close spread like 10w-30 or 15w-40 and change often.

 

[JHZR2]

ditto... I think the GC would be a nice fit. Saab turbo A3 oil (I dont think theyre importing it anymore) would also be a good fit.

Mobil 1 0w-40 might work quite well too.

JMH

 

[Marlin]

Turbo = asking for Mobil1

Also your car is not a normal Turbo, but a HIGH performance version. So it is even harder then the regular WRX motor.

 

[Tim_Siford]

quote:

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Originally posted by JHZR2:
I believe those cars come with M1 synthetic from the factory. ... Id probably have kept M1 in there the whole time.

---

Well, don't mean to throw knives at you but you're wrong. The Subaru STi comes with dino oil from the factory. It's the Mitsubishi EVO that comes with M1 from the factory. So, I've stuck to what SOA has asked for the car. Also, lots of STi guys are getting significant oil loss. Some of this is tied to using Mobil 1 really early in the motor's life. The general rule of thumb with the STi stuff appears to be around 6K for a swap to Mobil 1 with no problems or oil loss issues. Right now I am not losing any oil so that is a good thing.

Given that the STi came with dino oil from the factory I wanted to stick with a really high grade of dino oil. I chose the Mobil Drive Clean thinking that it would be pretty darn good ... AT LEAST as good as the stock dino oil. But, it is obviously shearing down. 1000 miles and it is just out of grade. The third oil analysis will be the charm here. If the third analysis also shows it shearing then it's a pretty cut and dry case not to use Mobil Drive Clean 5W-30 in the STi.

My main choice now is to figure out what to go with after this third drain of the drive clean. I am not going to run a 10W or 15W because I live where the temperature can drop to 10 below in the winter. That leaves me with any 0W or 5W multiweight synthetic oil. Normally it would be a no brainer and I would just choose Mobil 1 5W-30. However, some of the stuff I am seeing in the Subaru community and running M1 5W-30 in the STi is that it's just not as strong as it needs to be. It's just too thin. I just need to find the most shear stable oil I can with a 5W bottom end. Just not sure what that is. Normally, I would also choose Delvac 1 or Mobil 1R. However, from what I have seen don't both of these have a crapload of Zinc and therefore wreak havoc on the converters?

I'll take a look at that Truck and SUV formula too.

 

[glxpassat]

The truck and suv is delvac-1. Compare the specs. I even called Mobil and they told me this was true. From what I understand, and I'm no expert by far, the heat from that turbo is going to cook any dino and cause the oil to coke up. I would not be to concerned about running syn early on, as these days many auto's come with syn from the factory. I would not pay to much attention to the factory or dealer, just look at what happend to VW/Audi with their 1.8t turbo cars. Even if your car consumes a little oil at first it's no big deal and will probably cease after a while. The Delvac-1 is SL rated for gas cars so it should be ok. GC may be a better choice, especailly during winter as Delvac is really close to being a 10w-40.

 

[Tim_Siford]

quote:

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Originally posted by glxpassat:
The truck and suv is delvac-1. Compare the specs. I even called Mobil and they told me this was true.

---

Thanks! I guess it's the Truck and SUV formula for me then. I'll have to order some up and get it into the car ASAP.

t

 

[Big Jim]

Have you been using the newest Drive Clean? We have been told that the GF4 formulation is mostly Group III base stock and may do better than the older GF3 formulation.

 

[jthorner]

It seems like a lot of mass market 5W-30s quickly shear down. Some have said that this is all part of the "energy conserving" design of these oils.

Maybe much of the controversy over 5W-20 vs. 5W-30 is moot as so many nominally 5W-30 oils behave like 5W-20 oils after a thousands miles of use or so.

A shear stable 5W-20 seems like a better idea than a shear prone 5W-30.

Also, Mobil Drive Clean 5W-30, at least in it's SL formulation, generally doesn't get very high marks here compared to some of the favorite sons like Castrol GTX, Pennzoil, Motorcraft/Connoco and Chevron/Havoline.

John

 

[XS650]

quote:

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Originally posted by jthorner:

A shear stable 5W-20 seems like a better idea than a shear prone 5W-30.


John

---

Something to consider...
xW-20 vs xW-30 in modular Fords

Another look at the same data

 

[Palut]

That's a pretty high boost motor isn't it? Pennzoil has some pretty robust looking 30 weight oils, should be good for a short OCI. They even give you some cold cranking specs.

Why can't all oil companies do data sheets like Pennzoil?

 

[Motorbike]

One look at the boron and moly uptake on the 2nd interval shows how hard this motor can be on oil . I can tell it was driven a bit harder that interval if the analysis is correct and exact same oil was used . The oil is protecting well though but to go from one extreme to a hugely thick @ 40c extreme makes no sense to me during winter .

I'd place more focus on finding an oil that provides max protection throughout the interval with base oils that will not coke the turbo bearings even if it did shear some and left good TBN at end of interval so to not dillute the new oil. Oils with little to no VII's sometimes are not the ticket for all season use either in a few engines made today . I would rather see a beat up oil than a beat up engine and for that there are quite a number of synthetic 30wts available even if they are fake that will take you long n far .

They are not at Walmarts though ... at least the one's I would use

On another note from what I see the STI engines that are using oil seem more than likely to have had a combo of being overfilled with oil and or some poorly tuned aftermarket performance modules with advance curves that cause ping and piston ring de-stabilization

Comments on the latter ?

 

[moribundman]

quote:

---

I just need to find the most shear stable oil I can with a 5W bottom end. Just not sure what that is. Normally, I would also choose Delvac 1 or Mobil 1R. However, from what I have seen don't both of these have a crapload of Zinc and therefore wreak havoc on the converters?

---

What about Red Line 5W-40? Too much zinc?

 

[Tim_Siford]

quote:

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Originally posted by Motorbike:
One look at the boron and moly uptake on the 2nd interval shows how hard this motor can be on oil . I can tell it was driven a bit harder that interval if the analysis is correct and exact same oil was used .

---

I don't know if you can draw that conclusion just yet. The greater moly/boron in the first sample could largely be due to the factory fill. However, I have no analysis on my factory fill so we'll never know.

quote:

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The oil is protecting well though but to go from one extreme to a hugely thick @ 40c extreme makes no sense to me during winter .

---

Why? They are both 5W on the bottom of the scale so startup would be the same ... better in fact with the synthetic 5W-40 since it has better flow characteristics due to its synthetic nature.

quote:

---

I'd place more focus on finding an oil that provides max protection throughout the interval with base oils that will not coke the turbo bearings even if it did shear some and left good TBN at end of interval so to not dillute the new oil... there are quite a number of synthetic 30wts available even if they are fake that will take you long n far .

---

What would your recommendations be ... knowing that I can shear the Mobil DC in 1000 miles?

quote:

---

On another note from what I see the STI engines that are using oil seem more than likely to have had a combo of being overfilled with oil and or some poorly tuned aftermarket performance modules with advance curves that cause ping and piston ring de-stabilization

Comments on the latter ?

---

Sure. I've seen both stock STis and modified STis with the issue so that sort of rules out the tuning issue. With regard to overfilling ... good point. However, I just don't think that we will ever know since nobody will ever admit to overfilling the crankcase. Also, FWIW, the STi owner's manual states 4.2 qts for a drain/refill but everybody swears it takes 4.5qts. At this time, I still don't know who is correct. It's not as simple as just pulling the dipstick on the sti. The car has to sit for a good number of hours before getting a reliable oil reading.

 

[C4Dave]

The biggest problem you have is using SL/GF3 oils. The dino 5w30's all tend to shear out of grade. It's not just Mobil DC. But you're in luck. The new SM/GF4 specs address this problem. Find a GF4 oil and it should be shear stable.

On this board, you will see most people like Pennzoil, Castrol, Chevron/Havoline, and Motorcraft. Motorcraft is made by Conoco, which also makes Conoco, Phillips 66, Kendall, and Union 76. The Motorcraft 5w20 is particularly shear stable. I'm not sure about the 5w30, but I would assume it would also be shear stable. A certain following is also forming for the GF4 Mobil Drive Clean. The important thing is to get a GF4 rated oil.

 

[Motorbike]

First off congrats on the new car . Those are just too cool and thats one reason I replied . I also think it to be wise to run it in a little on dino like you are doing and agree the SM Mobil 1 30wts might not be the absolute best choice for these engines even though the valve spring pressure is light .

It a little difficult to reply to the quotes so here goes .

Take a look at the second generation Delvac 1 MRV numbers . My opinion is the 5w is a little misleading . Oils like this make for poor short trippers . Vi at 40c has alot to do with fuel mileage in the warm-up phase and too thick a vi @ 100c just places drag on the motors and don't roll over the internal parts as fast for cooling affect n more .

With the horizontaly opposed engines there is always some windage problems . If I owned one I'd stick 4.0 quarts in and keep check weekly assuming factory sized oil filter was used . If it stays at the level and Fe does not elevate your in like flint

Obvious to many here I prefer the Synergyn 3w-30 or 5w-30 . It's the cats meow for me with great base oils and absolutely killer barrier adds . It's a friendly well thought out oil that works in many engines and driving extremes ...even the Aunt Minnie type and will do what any 40wt will but it's not the only oil out there .

Short list

BMW 5w-30 High Performance Synthetic ACEA A3 - 5 bucks a quart . It's good stuff and overlooked by many and easy to find .

New Quaker State 5w-30 coming out thats A3 rated but not PAO

ELF Excellium 0w-40 . It's only 13.2 cST @ 100c and has around 1400ppm zinc - don't worry about the cat converter with modern ashless D/D packs IMO . I'd worry more about poor NOACK long term use .

ELF Excellium LDX 0w-30 A3

ELF Excellium 229.5 it's A3 rated

Mobil 0w-40 depending how cold it gets where you live

Citgo has a new synlube with HT/HS of 3.5 but not PAO

Pentosin Pentospeed A3 0w-30 will soon be in N America and the entire Motorex line from Switzerland will be arriving soon just for good measure .

Thats the only oils I could think of right off

 

[goodvibes]

If you want to stay with dino for a while, just use Schaefers blend 5w-30. Its got about 15% POA and a HTHS of 3.5. I remember seeing some test done by BOB that showed it actually left less residue in a test tube than M1 from extreme heating. You can swith to synergyn when your comfortable with break in without worrying about gumming up the works.

 

[Stinky Peterson]

Tim

I really doubt if you have a problem with your oil, its really rare to see shear occur in a engine. I don't have experience with SUS at 210 in fact I don't even know what equipment is use but I really doubt if you have shear. Also many new oils are borderline when it comes to viscosity so you can't really make a call without know the baseline. You might want to ask the lab to do a kinematic viscosity at 100C

Stinky

[ December 09, 2004, 11:06 AM: Message edited by: Stinky Peterson ]

 

[Whimsey]

I second the use of Schaeffer's 5W-30 Supreme Blend. It's actually a GroupII+ and around 20% PAO. I use in in the wife's Explorer, which is "hard" on oil and after an 8,200 mile OCI the viscosity was 60, a good solid 30 wt. It's also rated A3.

Whimsey