Having disassembled coaches failed motor, I can find no flaw in the crank or block that would cause the front 2 rod bearings to fail as they did. In fact, the #1 has a large oiling hole for the bearing. Aluminum engines are going to use oil period and 1 qt every 1-2K miles is not a big deal. I've used sythetics since delivery of both my VXes and never had a problem but I change oil religiously every 2500-3K miles. I've used Amsoil, Mobil 1, Syntec and even conventional 20-50w.