replaced 97 Bonnys 3800 series II motor now got water in oil

[union1644]

Blew a hole in the 3rd 3800 series II engine in my 97 Bonneville. My hubby REplaced it w a used one took it all aprt, cleaned and painted and when putting back together the exhaust doesnt align with new used motor, different flanges???? modifing to fit. I started the car, abit rough was smoking abit and shut off and got water/antifreeze in the oil. water pumps working so Now what?? uper or lower intake ? Head ?? Ive done alot of reading and trying to help but dont know much about Bonnevilles

[Jrs3800]

Its possible to have bad intake gaskets and would seem to be the most likely cause..

I have also seen them crack under a valve spring and push coolant out into the oil( Very Rare )..

Last several 3800 replacements we did in Bonneville we actually ended up suing an 06-08 L26 Series III 3800 from a Grand Prix to get a low mileage engine and simply swapped all of the aeries II parts onto it..

Recently we used a Series II from a 05 Buick LeSabre.. Long block is actually a series III with a series II upper intake and Throttle body.. some parts have to be swapped out to make it all work, wish it was plug and play..

It sounds to me like the engine you got must have come from a W body, as the rear manifold is different between the H body Bonneville and a W body car. And again check the intake gaskets to see if there are any issues... Would it be possible to return the engine and get another( lot of work I know )?