Hi Scotty,
I recently purchased a used (6 month old) GMC Sierra Denali Ultimate pickup with 3000 miles. I got a great deal and because it is a GM Certified used vehicle I got an additional year’s warranty, so in effect I have a 3 1/2 year warranty when a new truck only has a 3 year warranty.
The truck has a 6.2l V8 gasoline engine and the manual says it requires premium (91 octane) fuel. My understanding is that this is due to the high compression. What are your thoughts? Does it really need premium fuel?
Thank you,
Brad
the manual says it requires premium
Check again. I think it says "recommended for better performance", not "required".
Does it really need premium fuel?
No.
Just like Scotty always says ...
It's perfectly fine to use 87. You just lose a few horsepower and tiny bit of fuel economy.
The manual pretty much hints at this too ...
https://www.youtube.com/watch?v=PD6y2PtIu8Y
https://www.youtube.com/watch?v=dmNQ66AtyWk
This kind of question has come up many times here, please use the site search function.
https://carkiller.com/scottykilmer/?wpfs=premium+gas
The truck has a 6.2l V8 gasoline engine and the manual says it requires premium (91 octane) fuel. My understanding is that this is due to the high compression.
Whatever the owner's manual says. Lesser octane fuel detonates instead of controlled ignition and will seriously damage, and eventually destroy your engine.
No, lower octane fuel does not automatically cause detonation. All modern cars automatically adjusts spark timing prevent it.
Then what does "premium fuel required" mean?
You responded after I posted, lol. I didn't know there was a "depot" of sorts for different owner's manuals. Recommended vs required are different, lol.
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