there is a write up for an SR20, Nissan has one freeze plug with a screw thread for a block heater. It under the intake towards the Oil filter.
People are putting this in all the Nissans from Sentra's to Maxima's.
I will post a link if I can find or copy the material over if the link is blocked
2003 Pathfinder from 2004 SE 4WD
1997 SER 5sp Manual from new Rear Ended 2009 !!
Gone to the Knacker yard...
New ride 3.0 manual RWD not a Nissan !!! Gone 2016 from Hail damage.
1997 Sentra GXE from new .... Sold 2008
2001 Sunny N16 RHD from new (N16 Nissan Bluebird Sylphy) Sold