New should have been a first step on the list?
Run it, drive it to see where it is coming from. Put a few tanks of gas though it looking for the issue. No major damage is going to happen.
1. After a good run let it sit and check oil. Any milk? If so probably a head gasket or cracked head and the vapor is burning off through the oil.
2. Could still be a head gasket from a water passage, but you will have to pull plugs to see. One will be super clean.
3. If everything checks out maybe not getting up to temp and the exhaust temps are not able to suspend the moisture all the way out of the pipe?
