Red Line is perhaps the premier synthetic oil available in the US. The company is emphatic about not using its oil to break in an engine, except possibly for those engines that are among the few that use synthetic as a factory fill (Porsche, Mercedes-Benz, Corvette). See Red Line's website, <A target="_blank" HREF=http://www.redlineoil.com>http://www.redlineoil.com</A> . In these expensive engines mentioned, the cylinders have been especially ground and honed to permit the use of synthetics during break-in. In other engines, says Red Line, you should indeed use conventional dino oil for the first few thousand miles, then switch to synthetic. Using synthetics in a new engine will cause the cylinder bores to glaze (polish) so that the piston rings will not properly seal. This is an excellent means of stopping wear after break-in, but doesn't work while the engine is still wearing in.
This warning applies specifically to Red Line's excellent oil and may or may not be applicable to other synthetics, but be careful. I should also note that Land Rover recently issued a technical bulletin to its service departments advising NOT to use synthetic oil before the 7,500 mile service. There must be a reason. Ditto for tractors, obviously. I remember the Auto World report well, but it was very general and did not take Red Line's comments into account.
