Is there a way on the 3.8l to know if I have a cracked exhaust manifold without having to remove the cover of the manifold? The manifolds are covered under lifetime powertrain warranty and before I replace a bad CAT I'd like to see if my code goes away from a possible small crack in the manifold. Either way if you put a new cat in and there is a crack in the manifold it could fail anyway after all of that. I was getting an estimate on a CAT at a local small shop and the tech climbed underneath and put a flashlight up from underneath and said he could see some small black area on the manifold but the passenger side is a rough time removing the cover to get a good enough look. If the dealer does the diagnosis and finds no cracks I have to pay the $180 diagnosis fee. If they find an issue it gets covered by warranty.

Just tying to beat the odds at the dealer.