use BEHR for your heater core. There is a difference between the two brands, BEHR, being OEM, has the correct number of "tubes" in the core vs. NISSENS who tend to not have the same amount of cooling tubes, same with the radiators!! You should really replace ALL of your vacuum pods while you are in there, it would be a bear if you had to go back in after getting everything done. A long handled pair of needle nose pliers can be bought at Harbor freight will come in handy. They also make a long handled needle nose plier with the end bent at a 90 degree angle, you will use that one also. VERY similar to a 124 heater core replacement.