Did Australian cars have the same sludge issues that N/A and European cars had in the 1960's and 1970's? On one hand, I would think that they would have had this problem the worse, as you have really hot temps year round, and a lot of large, open highways throught the hot areas. As we know, one of the causes of sludge is the oil breaking down because of heat, especially with older oils. On the other hand, maybe you had less problems with this, as I believe the cars there are built with this in mind - larger, slower-running engines, larger rads and cooling passages, and stable temps to engineer oils for - no winter and summer hot/damp/cold fluctuations to deal with. Any of our friends from down under with thoughts or experiences on this? BTW, I do know the country a bit and the types of cars there - my folks are from there (Canberra and Armidale), and I have been there twice myself. The last time was 16 years ago, and all I remember of the cars is that they just seemed to be slightly bigger versions of what we drive here.... Great country and people for sure!