Yes yes, I know! Now comes the annoying question about the oil… the following: I drive (still ) the 5W30 from the , but wanted to fill in another. After the arrival of the FFH, but I should not use OW40 or 5W40, or similar, because the engine would be washed out and can generate ringing or rustling noises. My vehicle data: Mondi ST-200, year 99, 2.5 LTR. (as usual)