As I understand, the 3.3 spec is 5w30, or 5w40 for hotter summers. But is anyone running 0w? Regardless of full temp weight, a lower first number means less thick oil at cold start and therefore less wear, right?
Anyone running 0w30/40?
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Volfy
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0w is most often spec'ed by car mfrs for fuel efficiency reasons, since EPA tests using the OEM spec fill.
As long as you use a good synthetic 5w30 or 5w40, some of them actually have a lower pour point temp than some 0w oils. If you live up in the frozen tundra and really need to fuss over low temp oil protection, dig into each of the oils you are interested and download their mfr specs and look up pour point temp rating. I've seen them as low as -48F for 5w30 and even 10w30.
I've been to Alberta, Canada when it was below -40F. Most folks there just use an engine block heater.
As long as you use a good synthetic 5w30 or 5w40, some of them actually have a lower pour point temp than some 0w oils. If you live up in the frozen tundra and really need to fuss over low temp oil protection, dig into each of the oils you are interested and download their mfr specs and look up pour point temp rating. I've seen them as low as -48F for 5w30 and even 10w30.
I've been to Alberta, Canada when it was below -40F. Most folks there just use an engine block heater.
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That's interesting, I thought only the warm temp viscosity (ie going from 30 weight to 20 weight or even that crazy 0w16 stuff) would give you efficiency gains because that's where you spend the most time.
On the cold weights, it's not that my area's super icy, just figured a 0w should get moving a little faster at startup when you're ~150 degrees below running temp and disproportionate wear is occurring. But if a quality 5w gets moving as easily, I guess no real gain...
Volfy
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At operating temp, 0w30, 5w30 and 10w30 all should have very similar kinematic viscosity. That is what the second number signifies - regardless of the base oil's base-line viscosity (1st number), they all have 30 in their second number, which means they are all formulated (with long chain polymers added) to thin down like a straight 30 oil at higher temps.
Ironically, a 5w30 oil will actually warm up faster than a 0w30, albeit by a very small margin. This is because in thin film lubrication system, what produces frictional heat is not metal to metal contact. If that actually happens, the engine will self-destruct in very short order. Instead, what occurs is the shearing of the thin layer of oil film, which produces frictional heat. The higher that oil's viscosity, the more work has to be done to shear the higher-VI oil, resulting in more frictional heat being produced. This is how 0w30 has a higher fuel efficiency than 5w30. If you want that engine to heat up quickly in very cold temps, a slightly higher viscosity index (VI) oil actual helps. That is, as long as the oil's pour point characteristics allows the oil to flow quickly to the bearing surfaces where thin film lubrication occurs.
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Thanks for this, I was thinking more from the "thinner while cold = re-coat everything faster" angle than thicker shearing getting up to operating temp faster.
Any thoughts on running higher weight (40 vs. 30) preventatively when you performance tune? I've gone up weight on prior cars that were older/higher mileage, assuming more wear & looser tolerances, but on a relatively new engine I'd always thought flow > viscosity, meaning lighter weight would be better (and carry excess heat away better).
Volfy
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I've been discussing this very topic with my son, since he drives the G70 6MT. It's an interesting one.
Take 5w30 and 5w40. They both comprise of the same 5w base oil stock, with varying % of long-chain polymers added to modify their viscosity profile at higher temp - 5w30's viscosity drops like a straight 30 VI oil, and 5w40 drops like a straight 40 VI oil at elevated temps. With everyday driving, your engine internals mostly stay at the design (regulated) operating temp, so having 5w40 yields little benefits. The questions come when you operate the engine under extreme conditions, such as sustained track runs at high RPM. Certain parts of your engine (e.g. upper cylinder walls, turbo chargers, etc.) could experience substantial higher temp than perhaps other parts of the engine.
Under those conditions, the engine oil could continue to thin with even higher temp and could lose film strength, and with that the ability to sustain effective thin-film lubrication. All at a time when high piston velocities produce high shear rate on the oil film. Having more polymer content could help reducing the thinning of the oil and possibly maintain film strength. Notice I use the words could and possibly, because these premises are just hypothesis on my part - an educated guess.
Now, the downside... here we go again. There are always downsides. The more % of the oil made up of long-chain polymers, the less % is the base oil stock. The polymers help with maintaining VI at high temps, the base oil is what primarily does the lubrication. Besides, the polymer do get sheared up with use, eventually losing their effect.
What I told my son is: my estimate of usage impact between street to AutoX/track is probably 80:20. That is not the amount of time spend in each activity, which would certainly be higher - more like 99:1. I was referring to the impact of each activity stresses the engine oil. Going to straight 5w40 would likely be unnecessary, especially in the colder months. So... on the last oil change, we went with 5qt of 5w30 with 1qt of 5w40. Come Summer, with higher ambient temps and more frequent AutoX/track activity likely, we might change that ratio, perhaps 4qt to 2qt. All we are doing to tweaking the long-chain polymer content in the crank case. The more 5w40 we run, the more track time, the sooner we'll change the oil.
That said, can a guy run straight 5w40? Of course. There is nothing wrong with that. Most of us don't stress our engine all that much, and we change our oil far earlier than is absolutely required anyway. All this spiel is probably splitting hairs on a gnat's a$$. But since you asked... please take it for what it's worth.
Rob M
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Yes, I realize this thread is a year old. I have 2018 w/3.3L. prepared to do an oil change today before realizing my recent 5qt oil purchase was unintentionally mobil 1 0W30. I didn't have my receipt and didn't feel like returning it, so in went the remaining 3.5qt Mobil 1 5W30 extended mileage I had sitting around and 3.5qt of the 0W30. I don't expect to have any issues. Roast me!
Not to negate the points made above, but it's probably getting into "how many angels could fit on the head of a pin" territory, especially for a single oil change. Maybe worth sending in samples to Blackstone for analysis...I did mine a few months after posting this thread to get a baseline, and they told me that I was still showing signs of initial break-in at 18k miles!
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Snicklefritz
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Both of my cars get 5W-30 Mobil full synthetic at the dealer. This is listed clearly at the top of the receipts. But mysteriously the 2.0L receipt also says, further down, "0W20", what's up with that?
