Oil leaked into the coolant system, I heard from a couple meachincs it's a cracked intake manifold.
Is this a issue with the 3800 engine, has anyone else had this problem?
Thanks

 

It can be a common problem if you trust the tech get them to fix it unless you can get it done properly by someone else at a good cost.
If the engine had dexcool antifreeze the engine will be fine after the oil is flushed not just changed. If someone changed it to green coolant the engine is likely not gonna last more than 15-20k before problems will start to show.