Addressing fans who had gathered at the memorial to leave flowers, candles and memorabilia from the action films, Vin touchingly referred to his late friend as an "angel in heaven".
Paul Walker and his co-stars Vin Diesel and Tyrese Gibson
"The love that you’ve shown Paul… it's going to stay with me forever," said Vin. "I just want to say thank you for coming down here and showing the angel in heaven how much you appreciate him."
Vin also paid his respects online by posting a photo of the pair on his Facebook page, alongside a poignant quote by Scottish poet Thomas Campbell.
"To live in the hearts we leave behind, is not to die," wrote Vin.
"Pablo, I wish you could see the world right now... and the profound impact, your full life has had on it, on us... on me...," he added.
"I will always love you Brian, as the brother you were... on and off screen," added Vin, referring to his friend by his Fast & Furious character, undercover agent Brian O'Connor.
Visiting the memorial site on a separate occasion, co-star Tyrese was overcome by grief as he lay a single yellow flower at the memorial site. The star picked up a piece of the car wreckage to keep in memory of the 40-year-old actor.
"I will keep your energy with me forever #AshesOfAnAngel. Fast family around the world we live you and we love you," wrote Tyrese next to the photo.
"Paul is the heartbeat of this franchise and were gonna see to it that his energy and presence lives on forever #myhearthurtssobad."
Actress Michelle Rodriguez, who had been working on Fast & Furious 7 with Paul, also took to Twitter to pay her respects.
"I'm gonna carry this torch for you brother, with a forced smile on my face and I'm gonna open my heart just cause your telling me to," she wrote.
The movie will still be released as planned, but filming has been pushed back to allow cast members to grieve.
An autopsy is reportedly set to be performed on Tuesday, on Paul and his friend Roger Rodas who was driving the car and also died on impact. The coroner is waiting for dental X-rays for each of the men to help in identifying the bodies.