2000 Silverado Burns syn but not dyno. Possible?

[Gypsy]

A close friend bought this truck new. He is buds with the fleet manager at his job so he had the oil changed religiously every 3k. When he was ready to trade it in I offered to buy it. He was changing the oil that weekend so I gave him 5 qts of Mobil 1 10-30. I tlaked to him a month or so later to ask when I could pick it up and he informed me that it had burned a couple of qts of oil in 2k and he drained it and went back to dyno so it didn't melt before I bought it.
Is this possible. he said that with the dyno he never had to add oil between changes.

 

[G35_TX]

My friends 99 Z28 with the LS1 did the same thing. He went from GTX to Mobil 1, and he was going through quarts left and right. He stayed that way for like 9000 miles. He asked me about it and I told him to switch back to a dino. And he did, and his car stopped using oil. The LS1 has some weird issues with the rings and synthetics like to pass them easier than dino blends. It's kinda a common thing to use a dino oil on that engine due to this too.

 

[427Z06]

Quote:

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My friends 99 Z28 with the LS1 did the same thing.

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The early LS-1 had ring issues, namely flutter under high vacuum. You can't even buy the original rings from GM that were equipped with those crop of engines as GM has superceded the PN.

Many have had some success with GC, Rotella T-Synthetic, among others if you want to run synthetic.

 

[JohnBrowning]

It is normal for a vechile to burn some oil the first time you run synthetic in it after running dino. Then usualy by the end of the second OCI the consumption has stoped. It is simply the synthetic doing some very mild cleaning.