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high mileage oil weight?

62747 Views 18 Replies 9 Participants Last post by  Truck Guy
I have a 2011 silverado 5.3L which I got around 80k miles. Ive been running Pennzoil Ultra Platinum 5w-30 Synthetic since I got it. I was looking into running a high mileage synthetic like mobile 1 high mileage full synthetic but wasn't sure If I should stick to the factory recommended 5w-30 or Ive read that some people change the oil weight in high mileage vehicles. What do you think? I have about 97k miles on it now.

Thanks in advance for your suggestions.
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I am a bit lazy
I switch my 1998 Suburban(bought 2007 with 195,000 $2950-now has 228,000 runs great) to Mobil 1 as soon as I bought it
Used 5w30-but after a couple of years I switched to 10w30 Mobil 1
I did it because It had "slightly lower oil pressure" 17 psi-than I "liked"
I'm in a HOT climate-New Orleans
In made no MPG difference that I could measure-and no real reason to switch- 17 psi IS PLENTY
But it also has an oil leak-probably at oil pan-plastic timing cover junction
so heavier weight will probably leak slower when the motor is off

Anyway I now use the extended service 15,000 mile oil-change it once a year-but a year is just 3500 miles

So it probably wouldn't hurt to go 10w30-but you don't need to-GM calls for 5w30-they probably know what they are doing

Yeah 97000 miles is NOTHING for a modern engine-they shouldn't break before 200,000 miles
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