Quote:
Originally Posted by zikzak
A bad radiator or water pump isn't reason to suspect a blown head gasket or other serious problem, especially on a newer car. It can be a very difficult thing to diagnose sometimes.
Usually blown head gaskets are easy to detect. Just take off the cap where you put oil in and you'll see water mixed in with the oil. If it's gray or brown, or anything but black, there's coolant in the oil.
If it's a tiny head gasket leak, it sometimes only leaks when the engine is cold. Then as it warms up it seals. In that case, the water that made it into the crankcase boils off. So you'll want to start the car when it's cold and then shut it off after a minute, and do the oil check above. If your coolant level is dropping over time, that's another clue.