>>>*The leak can usually be isolated by using a radiator pressure tester to bring the system up to 15# or so, then simply watch for where the leak appears.

*The "paper burning" comment interests me, I noticed a similar smell from my old Camaro. I even looked around under the hood for insulation or something like that, finally I figured out the old engine (200,000+ miles is very old for a GM engine) was using a small amount of oil, the smell was actually coming from the exhaust.

Just a combination of oxygenated fuel with oil residue and the Cat dealing with it, I believe. If some coolant is reaching the combustion chamber, then this will increase oil usage some. That might be what is going on.....*EB