99T 306 HDi oil capacity - 4.5 litres with filter change. As my car uses <0.1 litres between changes, when my hot oil has stopped draining out of the sump, I throw the first 400ml from a 5-litre can in the engine as a quick flush, replace the drain plug and refill with the remainder, then all the drainings go in the can for recycling to the tip.
.. I've just checked my handbook. It's on p.107 under Technical Data - 4.25 litres with filter change. I find that 4.5 ends up exactly on the top mark after a total drain, which I guess many garages will not achieve as they may not wait long enough, nor tilt the block to the rear (or may even use suction through the dipstick hole as draining from below means removing the sump guard).
Thanks Andrew. I suppose being half asleep whilst trying to read the manual didn't help!
Do you know if anyone makes a 306 HDi workshop manual?
Haynes just do one for the petrol, and then I suppose you buy another for the engine.....
The only 306 HDi workshop manual I believe exists is published in French in the "Revue Technique" series, available in many French hypermarkets (ISBN 9782726863916). Even if your French is up to scratch, the text is very short on detail and nowhere up to the Haynes standard. (To be fair, there is a warning that the book is intended for professionals and that details thought to be obvious are not included. Huh!) It says the oil capacity (including filter) is 4.5 litres.
I believe one of the Citroen manuals covers the HDi engine.