I'm trying to find a vacume leak in my 06 MC with the 3.5 v6 in it and is there anywhere that they are noteorious for vacume leaks? I can hear a whistle once and a while.

 

i think you and me have the same problem(i have a 3.9). are you leaking coolant? or see oil mixing with your coolant?

 

Im not shure i'll check what's wrong with your mc that oil and coolant is mixing? I havent really looked at my coolent short of looking at the reservoir to see if coolent was in there and when i check my oil i dont see signs of coolent but I will check tomarow and get back to you.

 

When you hear the whistling, have the engine running and spray all vacuum lines, intake flanges, power brake booster and anything that uses vacuum with starting fluid. It will get sucked in at the leak and change the RPM's Don't worry, it evaporates fast, you will never know you even sprayed it on your stuff.