[Cobalt]

Blame Porsche not the material. They didn't properly treat the parts and people don't properly maintain them.

Magnesium needs to be protected from the elements. Exposed surfaces to moisture, salts, and grime will eventually break it down over time. If properly protected will last as long as an aluminum counterpart. I manufactured Magnesium and aluminum parts for the DoD and many of my parts were still in service decades after we made them. Everyone thinks parts should last forever. The fact is take care of your car properly including checking the magnesium parts occasionally based on driving and storage conditions and they will last as long as the car. My 94 turbo wears its original fan and looks like new still to this day.

I have a fan with 144k track miles and when I last grit blasted it and painted it last year it was as good as new. The parts fail due to lack of maintenance and Porsche wasn't building cars to last but to perform. Also there are several types of magnesium alloys. All of which have their pros and cons and are effected by the elements differently. Porsche used what is called an aluminum based alloy which has about 9% aluminum in the alloy. This alloy requires a chemical conversion prior to paint to last. Porsche bypassed this step and used a paint to protect the fans and valve covers. This was a bad choice but no doubt the cost factor played a roll. The fans are still made of magnesium today and there is no better alloy for the job. The only option is some form of composite material. Carbon fiber or fiberglass would work maybe one day we can 3D print them but for now take care of the painted surface and you should be good for a long time.

Porsche switched back to aluminum valve covers due to cost. Magnesium can be made from the same tooling as aluminum. However the processing costs are higher than aluminum. I made some Chinook/Blackhawk/Seahawk/Super Stallion parts to name a few in both aluminum and magnesium and I charged nearly double for the mag part as the aluminum. I still run original mag valve covers on my 144k mile engine and so long as I keep it protected they are doing just fine. There are also better mag alloys with a higher purity and can withstand corrosion far better than the alloy used but this adds even more cost to the product.

144k miles on these mag valve covers and they are still working perfectly. Ironically the engine sheet tin was in far worse shape. But that car sits outside all the time under a cover.



This is my original 94 turbo fan and it has heald up perfectly but the car is a garage queen with only 38k miles.