Hello, about 2-3 months ago the BC indicated that the oil level was low. I was a little surprised, because half a year before an oil change was made. I couldn’t quite explain it, thought the workshop had not filled enough and the engine used something (km stand about 160 t). Then I noticed a little oil on the ground (very little, very unclear where it came from). In the cooling water tank was also oil. I have now replaced the oil cooler. From the cooling water circle. I thought, if I blow in with the old oil cooler and keep the other hole (from the water cycle), then air can escape over the other cycle. But that wasn’t so. Can the oil cooler still have been leaking or does something else come into question? Otherwise I hadn’t noticed anything, engine power normal, temperature indicator max. in the middle. VG V40Oldi