sbljr

IF break-in were truly important it would be on a big red sticker in the middle of the steering wheel. Even liquid-cooled engines may break-in *slightly* better if the "vary speed" mantra is followed, so they put that in the manual, but it's not nearly critical as it is with say aircooled motorcycle engines. If it were there would be rpm limitations too (e.g. not above 2500 for 1st 50 miles, not above 3500 until 500 miles).

I had an S10 pickup a few years back which brand new at -0-mies was driven from a dealership in Denver to one in Topeka, straight across 525 miles of flat, boring, constant-speed Interstate 70. IOW, the exact OPPOSITE of what is recommend for the 1st 500. If it hurt it anything at all, it must be something that only shows up at higher mileage--for the 40K miles I owned it before trading on a Colorado, it ran perfectly and never used oil like a badly broken-in bike motor will (what the S10 had was an inline 4 of similar displacement to the HHR, but it was an old Isuzu design not nearly as advanced as the Ecotecs).