Why do they keep giving me 10w-30?

[bamachevy89]

I brought my '04 Tahoe in for a 3k oil change a couple days ago after traveling for Christmas and once again, they put in 10w-30 oil. I asked them why and they said "all gm currently distributes is 10w-30." I use regular oil, not synthetic and they have been putting 10w-30 in it for over a year now. Is it doing any harm? Should I start bringing it to Valvoline to get the oil changed where I will actually get 5w-30?

 

[energ]

not too big of deal, maybe a very small difference in crank time(a little longer) and a little bit longer to get to operating temp
you may or may not notice it, but if you did it would be in very cold weather
but once they both get to operating temp they are essentially the same

 

[bzbatl]

The difference between a 10W and a 5W oil is pretty nominal, especially in Alabama. You may notice a cold cranking difference if you moved to Canada.

Lower numbers mean "thinner". In a multi-weight oil, this means it's 5W (thin like water) cold, and then 30W (thick like honey) at operating temperature (around 200F). Don't ask me how this works, I'll just answer "polymers". Go watch Discovery Channel if you want to know how that works

 

[bamachevy89]

Ha ha, thanks for the replies. It just got me wondering again last night when I saw all these posts in the new body style forum saying that GM recommends 5w-30 for a reason and thats what should be used. I may switch to synthetic soon anyways. Thanks.

 

[bzbatl]

Unless you're willing to splurge on moly synthetics (Motul, Royal Purple, AmSoil) - I'd say stick with Shell Rotella T from Wal-Mart. $16 a gallon and highly rated from real-world testing.

Also, start doing the changes yourself, it takes 20 minutes and cleanup is minimal. Your soft benefit is you know it was done right.

 

[boostaholic]

Rotella or the regular blue bottle mobil is good stuff. I get a deal on royal purple and it is noticeably smoother and pulls harder too (I installed ngk tr6 plugs gapped to 0.35 at the time as well).