Water can enter the engine oil if you have a rambunctious 8 year old boy who wants to help his dad out by filling the engine with oil, except at 8 years old, water will work fine. The next thing you know he is filling the gas tank with the garden hose. Ask my dad!!
Realistically speaking over 90 percent of the time a head gasket has gone bad or in the case of an engine that uses aluminum heads, the anti freeze, especially the wrong type will corrode the aluminum too. Make sure you use the proper anti-freeze/coolant in your engine.
For all practical purposes, older engines are generally the victims, and that is because old gaskets wear out and fail. It is not always that simple, but lets stick with that. So if you have an old engine and it starts to leak water into the engine oil, it is possible the engine is tired and needs replacing.
Although there are plenty of low mileage cars that overheat for whatever reason and cause the heads to crack or warp from way to much heat. In cases like that, the engine may well be worth the repair cost.
The bottom line is a qualified mechanic is the only person who has the ability and tools to get to the problem as fast as possible and provide a solution. I don’t know how many people frequent forums for answers to their engine questions. But, I want the folks who do enter into forum discussions to tell me in the comment box how many times you got a good answer.
If you need solid advise, you should ask a professional. We can’t diagnose your problem over the phone, and we won’t try too. If you call GotEngines.com @ 1-866-320-1065, we can provide a multitude of engine replacement options after you are sure you need another engine.