What does it mean when there is oil in my coolant?

Hello and thank you for using JustAnswer. My name is \*\*\*\*\* \*\*\*\*\* I will do my best to assist you. During this conversation you will be given an automated offer for a phone call. You may accept or decline that offer.I don’t personally offer this service so if you take this another tech may call I’m sorry that you’re having trouble with your vehicle. I will do my best to help you resolve them. Please understand that I do not know your knowledge or capabilities so I may need to ask questions to find out basic information to help solve your specific problem. My aim is to give you the best service possible and to help you. If you have any questions or concerns, please don’t hesitate to let me know. Sometimes it may take a moment for me to respond because I may have to look up information about your concern. I appreciate your patience and will provide responses as soon as possible. It depends upon the year, make, model and engine size - possible causes are headgasket, engine oil cooler if equipped, turbocharger if equipped, intake manifold depending upon the engine Thanks for using Just Answer and letting me help you. I hope I provided what you needed. If you find more help is still needed, let me know by listing out any remaining questions you have on this concern. I hope the remainder of your day is well.

Pontiac g5

Hi need the year and engine size as well