Hello all. So my 03 Crown Victoria is about to hit 180k miles and now is burning enough oil to see blue smoke if you Rev it up after it has been idling for a few minutes. I suspect valve guides. I'm done with dumping any more money into this car. My last oil change I used Castrol Magnatec. I'm gonna have to switch to some sort of HM oil or maybe a thicker grade than 5w20. What's everyone's opinion on either using Castrol Edge 0w40, Pennzoil HM 5w20,5w30 or use a 15w40 Rotella T4 or Delo 5w40? It's an ex cop car so it's pretty thrashed. Thoughts?