The 2006 model has a diesel 1.6 407. When the engine warms up, the oil pressure low warning lamp comes on when it is idle and the rpm ends when the speed is high. It also burns until the engine warms up, does not warn when the engine temperature rises above 85 degrees. oil oil filter oil dispenser changed oil 10 40 was put. There is no reduction in oil. what is the solution to this problem. service cannot say a definite fault. has already changed all that I counted. They say that the oil pump will change at the moment, but when I say there is the faulty one, they cannot say for sure. what should i do now