Differance between 5-30 and 10-30

[tig1]

I saw this today and thought some may find it interesting.

http://www.mobiloil.com/USA-English/Moto...mperatures.aspx

 

[2oldtommy]

Use 5w-30 year around and forget it IMO. FWIW--Oldtommy

 

[mechanicx]

Yeah I think back when 10W30 was recommended it was more sheer stable and less volatile than the 5W30 of the time. Nowdays SM and SN 5W30's sheer stability and volatility is better than then.

 

[CATERHAM]

What Mobil unfortunately doesn't go into is the low viscosity index of 10W-30 oils vs 5W-30. This is because the 10W-30 oil is formulated from heavier, lower VI base stock oils.
Comparing M1, their 5W-30 has a 172 VI vs only 146 for the 10W-30, meaning the 10W-30 will be noticeably heavier on start-up at all temp's even at 100F (still a cold start for engine).
Once up to normal operating temp's both oil's will have the same viscosity.

The 10W-30 grade is largely redundant with synthetic oils as it offers little if any advantage in terms of shear stability over a 5W-30 synthetic. It does hold more of an advantage in that regard with mineral based oils but again even 5W-30 mineral oils are proving to be very shear stable.

The 10W-30 is fast becoming a legacy oil grade as it is rarely specified in PCMO applications today.

 

[Chevys_n_Hawgs]

Not to hi-jack the thread, but I picked up about 20 qts., of Quaker State 4x4 synthetic 10w-30 last summer, on clearance at AZ, for $2.49/qt. My truck is spec'd for 5w-30. It is a 2008 Chevy Silverado, with the 5.3 engine. Is there any problem with running it in the summertime? How about if I "blend" it with my 5w-30 QSUD? Thanks

 

[fdcg27]

No problem at all.
Your OM may even allow for the use of 10W-30 at warmer temperatures.
The two OMs of our two Hondas allow for the use of 10W-30 above 20F, while the Subarus allow for its use above -4F.
Under typical spring/summer/fall conditions, a 10W-30 will work just fine, although it will be thicker than a 5W-30 at cold start.
I use some 10W-30 during the warmer months simply because I bought it at a price too good to pass up.

 

[tig1]

The reason I posted this was many here talk about using one oil for the summer and another for winter. I actually did thid in the 60s for a while using Valvo straight HD 20 wt in the winter and HD 30wt in the summer. Since I started using M1 5-20 in 1978 I never looked back with the oil switching thing.