I talked my neighbor into buying an 09 550H1 last summer. It has very low hrs and miles on it. Today he called me and said when he changed the oil there was coolant in the oil. He added about a pint of coolant to the radiator. He said it has not overheated. Is there something on the 550s that is common that would cause this? My 500 has caused no trouble at all but I know nothing about the 550. but at first thought I told him maybe head gasket or water pump seal but then again I don't know how the water pump system works on those. Any ideas would be great.