What is the difference between Mobil 1 5W30 and Mobil 1 10W30?

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May 28, 2002
Yes, they are both 30 weights so hot specs will be same/similar... However, the 5W allows for starting at -30 C as opposed to -25C for a 10W...so the decision is a cold-climate one...depending on your climatic conditions... And a final note, the 10-30 has a smaller spread and thereby may be more stable/resistant to viscosity change...
With the new Supersyn formula though, thinning out is no longer a concern with the 5w30, from the many UOAs we've seen on here, I can't recall any that have shown it to thin out. So even though the 5w30 Mobil 1 has a bigger viscosity spread than their 10w30, it's not causing this oil to thin out at all. With the old Trisynthetic 5w30, thinning out was definitely a concern, I have seen a few UOAs in the past where that oil turned into a 5w20 rather easily.
For Minnesota in the wintertime at least 5W-30 Mobil 1 would be better. 10W-30 could be used in the summertime.
The only main difference I can find is that the 10W30 has a slightly higher pour point. Otherwise, it seems as if they are exactly the same oil. I don't think their viscosity at 100 C is much different ethier. Can anyone identify any major differences? [ September 25, 2003, 12:28 PM: Message edited by: MinnesotaNole ]
Look at their cold cranking specs, that's where the big difference lies. When it's below 0F, you'll notice the 5w30 will allow your engine to turn over much easier than the 10w30 would.
Which would be the "best" in the moderate Central California climate....... for a new car....with short drive intervals (3-5 miles)?
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