trollbait,

good post. i didn't get all the details, but the kid's 10k miles on a "year old" car could have really been 18 months of all short trips. and walmart could have been using used oil.

i think toyota's sludge issues were related to the engine block design. they changed to coolant ports(i believe) making the oil heat beyond what it was capable of handling.

changing oil 3 times per year? makes sense for conventional oil i suppose. i don't use the stuff myself.

Should stated it was in reference to conventional oil.

Synthetics are more heat tolerant. Which means less scorched particles, and thus less acid formed in the same time. I usually go 10k miles when using synthetics.

Toyota was trying to save money on manufacturing. I heard the blocks had fewer coolant channels. Whatever the reason, the oil got cooked.

The lesson is, when you have problems with the engine and oil is suspected, get the oil in the engine tested.

The HHR has GM's oil monitoring system. During the spring/summer it called for a change at 7500 miles. In fall it went 6700.