Isn't it more or less in the middle of the space between the radiator and the top of the engine with the dipstick sticking out of it? (Flip off 2 spring clips on the sides and pull out)
Just to left of centre, has an orange dipstick sticking out of it, black plastic, top either has clips or unscrews.
Stewart
BXs since 1993 built 1.9 TZD turbo, got a S2 Xantia estate, brilliant car! 2013, Xantia HDI LX 110 2000 new car with 122,000, l C2 HDI Rusty rocket, C3 Picasso HDI new to me.