oil in water on 2000 Cadillac Catera

i have oil in the water but not in the block. just had oil changed and they put 7qt in it.

Asked by for the 2000 Cadillac Catera
It's a very common problem with this model. You have a bad oil/coolant heat exchanger which is located on top of the engine. Fairly expensive to replace.
2 more answers
Than one of the tanks on the side of the radiator may be bad
Mine had water, as in white milky substance, on my oil refill cap - none showing on dipstick. I was told that sometimes due to humidity, etc. it will acquire moisture in the oil. Was recommended to clean refill cap and recheck in a few days. For mine it was as simple as that. Hopefully you don't have oil/water mix on dipstick. Good luck!