If engine oil ends up in the radiator, it usually is due to a cracked head or blown head gasket. If the crack is adjacent to the oil pump, the resultant pressure can blow either the radiator or a cooling hose.
To fix an oil problem in the radiator, first pull off the cylinder head and review it. If the issue is a bad head gasket, the part needs to be replaced, according to the Car Talk website. If the head does not feature any cracks, the next place to look is the block.
According to Eric the Car Guy, a blown head gasket denotes that the combustion system is leaking oil into the cooling chamber of the car. Head gasket failure is often the most frequent reason for such a leak. Another possibility is that a leaking intake gasket is causing an oil problem.
Eric the Car Guy notes that seeing white smoke coming out of the tail pipe when the temperature is at least 50 degrees Fahrenheit is a strong indicator that a combustion leak is affecting the car's cooling system. A leak-down test can determine whether a combustion leak is a problem. To conduct the test, direct compressed air into the cylinder. Look for leaks. Bubbles featured in a radiator after the pressurization of a cylinder can also be proof of a combustion leak.