Most likely a cracked cylinder, a cracked block or a blown cylinder head gasket.
Do a compression test.
Check for other external leaks.
Most likely the head will have to come off, for further investigation.
No. Antifreeze should not mix with engine oil in any vehicle.
You have a mess.
NO!!!! do not do this, oil is oil, transmission fluid is transmission fluid, and antifreeze is antifreeze, do not mix any of these, it can perminately damage your engine.
I'm not a mechanic / technician but I believe if antifreeze is getting into the engine oil it is because of a bad head gasket , or perhaps the head has warped
cracked or warped head/blown head gasket.
It will destroy the engine from lack of lubrication and overheating.
You can't "mix colors to get antifreeze."
You can fix oil that is getting mixed with antifreeze in a Ford Econoline 250 of the year '98 by replacing the head gasket in the vehicle. A blown head gasket will cause the antifreeze and oil to mix.
Oil/antifreeze mix is usually caused by head gasket leaks or valve cover gasket leaks.
Make sure you use the red stuff as the green antifreeze tends to rot the oil cooler and causes other problems too. Do not mix them either.
you can mix water with anything
If you start and warm up your engine: 1) The oil gets very foamy and mucky, and does not circulate through the engine properly. 2) The water in the antifreeze can heat up until it turns to steam, which expands with great force, and breaks some part of the engine. It's best to have the oil changed. That will empty the engine of the oil and antifreeze mix.