Left my punto for service in RDC, Chennai as I was going for a long trip next week. The service advisor called me now and said that when he tried to top up the fluids the coolant is completely dark as the engine oil got mixed with coolant. He says the need to completely flush the oil's, fix the issue and refill the oil's. I really do not have a clue what is he saying. Can experts help me understand this? The problem I had is I was hearing sound similar to running water when I took the car for vellore 15 days back. He says this sound is due to the engine oil mixing with coolant.