Ok will check the locations you have mentioned. The coolant was flushed and the coolant tank was just replaced a week ago. Earlier the coolant tank was almost dark and the coolant was very viscous with some deposits. Its bit better now. I asked if there is any oil leak, the technician said no, he said the coolant is not oily. But will check anyways. My coolant tank has been "dark" for 3-4 years now. If there is minor leak in radiator, do you need to replace the entire radiator?? Whats the cost of the radiator?