He has been fielding telephone calls from six mobile phones and a landline, connected under a gazebo at a shopping centre in Centurion, south of Pretoria.
“It gives me such great pleasure to do something for a good cause... people take notice," he told AFP in a phone call 38 hours into the attempt.
To keep talking, Van Zijl said he relied on family and Facebook friends to call him.
“When they don't call me, I call them,” he said.
According to the Guinness World Records, the world's longest telephone conversation by a team of two people lasted 54 hours and four minutes.
Van Zijl claims to have broken 39 unusual records, ranging from dancing to disco music non-stop for 345 hours and to sitting for nearly 13 days in a jacuzzi.