For anyone running the 3.1/3.4 L GM engines I highly recommend getting an oil analysis done of your used motor oil from time to time. I started doing so about nine months ago, and the most recent analysis came back with clear signs of coolant getting into the oil.
Luckily our '02 Olds Silhouette had the included GM extended warranty which covers to 5 years, 60,000 miles. Our van was at 2.5 years of age and 41,000 miles.
The oil analysis caught coolant traces well before there was any visible sign of water mixed with the oil. This is good as very little bearing damage had a chance to happen.
The dealership was excellent about checking out the problem and fixing it at no charge.
If you have one of these vehicles I strongly recommend periodic oil analysis to find the problem early before major engine damage happens.
I get mine done by Blackstone Labs,
Other than my customer relationship I have no ties to Blackstone or any other oil analysis place.
John