Whilst I no longer fiddle with cars (rebuilt a few from the ground up in much younger days and now got rid of most tools), this reminds me that I recently had a Rover 75 estate with water problems - footwells like washing up bowls! Had to remove most internal fascia to access weeping joints on the rain drain system. My trusty screwdriver head set covered all the fasteners there and then a long piece of plastic coated spring wire reamed out the pipes. Lots of silicon sorted it.
Now got a 2.2L diesel Espace and won't touch that - far too modern for me to be able to do very much beyond the standard maintenance with standard tools.