GM Break-In Oil?

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Jun 11, 2003
I've read on here that some companies (Honda, ect) use a special break-in oil (high content of moly) and that you shouldn't change it for a while. I just bought a new GMC Sierra 2500HD with the 6.0L and was wondering if GM uses a break-in oil? Also was planning on running Schaeffer 5W-30 with a Napa Gold Filter, does that sound good? Thanks, Jeff.
GM used to add a break in additive that was loaded with ZDDP and other ep and aw additives. They quite this practice once GM decided phosphorus and zink were killing cat. converters. You used to be able to buy the same break in additve over the counter for rebuilt engines. THe additive was mostly severly hydrotreated petrolem and ZDDP.
Good old GM EOS! (Engine oil supplement). I used to add 1/2 a bottle of this to my 10W-40 dino at every oil change in my 327 Nova. [Smile] Does GM still sell EOS? [Confused]
In Canada you can still get GM EOS. I've seen it at the dealers still. They also sell something called the Lubricity additive, which worked very well for me when I first got my car and it had a noisy valvetrain. The rest of the noise went away with my applications of Auto-rx. [ June 13, 2003, 09:33 AM: Message edited by: Patman ]
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