Trent, Thanks heaps for the photo. It looks like a standard right hand thread so I will be able to remove it with a good stilson or footprint spanner. I would not have been game to tamper with a push fit tube. I'll just have to be careful with cleaning it before removing it, and cleaning the thread before replacing the tube. I suppose it would be good to replace the oil and filter as soon as it has been tested when finished. I will ask at auto spare part shops for a high temp. thread tape rather than use a plumber's Teflon tape. I wouldn't want tape fragments clogging up oil lines. many thanks, Geoff.