Just an update on my engine. I completed the 3000k oil consumption test ( took a while as we do not do a lot of driving in the collie) with an estimated result of 2.3l per 10,000k. Dealer said that was within spec for the engine. I told them i was not happy with that so they said I would need to contact Holden directly and lodge a complaint with them. Contacted Holden Customer Care and was told two more consumption tests would be required so back on the merry go round we got. I had just started the second test when I found out about the thicker oil being used. At that time i decided enough was enough I was not going to continue months of more testing with results that would be dubious at best. I researched the Qld Office of Fair Trading website which was very helpful, they even have template letters you can use to get you started. I sent the letter to my dealer and in it I made it clear I would not be completing any more tests and wanted the thicker oil out of my engine. The only thing I would accept was a new engine or I would be proceeding with a claim through Fair Trading. As was suggested by Fair Trading I gave them 10 days to respond and respond they did. It took two days and I had the general manager of the dealership on the phone telling me that Holden had decided they would replace the engine and they would also provide me with a loan car during the 4 days it would take to do the work. It took them under a week to get the engine and it was fitted the following week, so in just over two weeks from sending my letter it was all done. They replaced the complete engine (minus all the bolt on stuff of course) so am happy with the end result. Hopefully this will see an end to my oil consumption problems.