If your 3/8ths drive is a loose fit it's likely the square drive is 10mm. Your car is a '74 so the engine is likely to be a "metric" motor--8 bolt crank. I don't know if such a tool is commonly available but I can tell you having worked for Peugeot dealers the "factory" tool for removing the engine drain plug was an inexpensive two ended (one end bent at an angle) 10mm square drive bar. Find someone who works on Peugeots :-) and you'll have the tool you need (if it is indeed 10mm). I can "loan" you mine--but would require a substantial deposit to assure return. -- Dave