Dazed and Confused
Join Date: May 2012
Location: Upstate New York
Re: Nav suspension leak 2008 "L"
If they're original, probably pretty good. Given they have the same design and made from the same material, their life span from normal wear and tear is going to be near the same. Soap bubble will pick up leaks, a pressure gauge on the vent, a pressure gauge on the inlet to see if it back leaks.
Ever notice that there's so many high performance parts available for GM products?
Did you ever think that maybe they NEED them?