There actually were some cold climate failures attributed to the sludge problem from moisture intrusion. The baffle plate in the filler tube was the fix for it. Crankcases were found full of milky sludge before it.The interval on the timing chain is something like 250,000 miles. This engine is built to last, as long as you maintain it. And contrary to what some people say, it is NOT a sludge engine. It gets that rap from the foamy 'snot' that accumulates in the oil filler neck and cap. This is simply due to the way the PCV system is designed and the fact that the filler neck is plastic.
That said, mine just rolled 120,000.