I need to replace the radiator in my 1984 245 dl and when I check for parts online they have both radiators "With Patented Sensor Locking System" and without it. How do I tell which one I need. Also, do I go with metal core or aluminum and plastic?

 

I'm on my 3rd radiator on my 740 (310K miles) and I went with the aluminum core with plastic tanks. My last one was brass and eventually rotted out. It was only $150 so not a big dollar hit. Mine came with the standard push in rubber sensor mount.