I have had considerable experience with aluminum thread failures in non-automotive applications.

While aluminum corrosion can be a nasty problem, the problem is more often caused by over tightening during the initial assembly and "pulling" the aluminum threads by the stronger steel mating threads. A pulled thread is only revealed when dis-assembled and the aluminum thread material comes out with the mating steel fitting. No special removal technique will save an aluminum thread that was "pulled" at installation time. A "pulled" aluminum thread usually does not leak in service since the thread is not a sealing thread. It is only a mechanical joint holding the two mating parts together.