peugeot oil mixing in coolant

Hello friends, I bought my 206 1.4 HDI 2003 model vehicle 3-4 days ago. Two evenings ago, I saw warning lights that I could not understand while driving on the road. When I looked in the morning, there was no oil in the car and oil was mixed in the cooling water. I immediately showed it to the master, he said it was from the oil cooling part. We changed it. , when I checked today, the car had reduced oil again and there was oil in the coolant again. What do you think is the solution? The former owner of the vehicle is a really good boy, he says he never sees heat, which does not exceed 80 for me either.

If not, it could be the oil cooler. The master has changed that. Oil entering the system is not easily cleaned. It is necessary to clean it by constantly changing the coolant. Therefore, oil may appear in the expansion vessel for a while. The important thing here is to observe whether the amount of oil in the expansion vessel is increasing or decreasing.

Yesterday the master cleaned with powder detergent. I was surprised, but I said there is something he knows... I drove my car for about 20 km today, there was no oil in the water... I think it's a pleasing situation now.

Yes it's a correct method