Tried Castrol Synthetic 5w-30 and now my truck smokes in the morning when I start it

Has anyone of you guys experience this? I recently switched to Castrol Synthetic 5w30 and I've been noticing that my truck would smoke in the morning or when the engine is cold at startups. My truck has 72k 4.0 and other than a KN air filter, it's stock. Anyone of you guys experience this at all? Is there something that I should check or change? Should I switch back to conventional oil? I'm not sure if it was smoking before I switched to synthetic...I just recently noticed it...should I be worry?

 

If it is wispy smoke and then clears up once engine reaches normal operating temperature, given your milage, You most likely have overfilled the oil and the smoke is the blow-by which pools when engine cools.

Give it a hundred miles or so. You could drain some fluid - 1 cup (max) to see if it goes away.