Amazing what can be done when one gets off one's arse and on his back. The 1.8 306 went up on ramps at the front this morning. Armed with pillow for head, torch, fresh rag and camera, I hunkered in. This is with the car facing downhill on a moderate driveway, so the car is at a very slight 'nose-up' attitude. Almost immediately I caught sight or "purest green" (coolant) on a metal tag, which is the lowest point. With engine running, the leak is at the total rate of about a drop of coolant per 5 seconds. The leak was from a point to the right and above that, on the left end of the engine. Start your focus about 70mm along the lay shaft to the left of the back of the engine; you will see a 'cross' in the back of the cylinder block. Look up a bit further, and there are two buttresses in the block running vertical. The one on the left receives the oil dipstick, while its neighbour not far away, carries a screw-in plug; it may be a pressure relief valve or the like. The web on which they sit forms a ledge, and I believe the crack runs along the intersection of that ledge, or web with the block. Because of limited access, I have not yet had a direct peek at this crack, only from below. I will take the car down from the ramps and now that there is somewhere specific to look, will scan from above rear of the engine bay, perhaps manana. Adios