SABC radio news reported that its team was interviewing striking workers at Stofland informal settlement when stones were hurled at the vehicle.
A picture of the car, showing a shattered back window screen, was posted on Twitter.
No injury was reported.
Last week, another journalist's vehicle was torched during protest action. The car, which belonged to an Independent Newspapers journalist, was overturned in De Doorns and set alight on Wednesday.
Police patrol attacked
Earlier, police said one of its foot patrols was attacked in De Doorns on Monday morning.
Warrant Officer November Filander said the officers were attacked around 03:00 while patrolling an informal settlement in the Western Cape town.
"I was informed that the officers used a stun grenade and not rubber bullets to disperse the group," he said.
The three were arrested for public violence. One was allegedly found in possession of dagga.
"The affected farm striking areas are quiet at this stage. Police are still monitoring these areas."
Farmworkers in De Doorns want their minimum R69 daily wage increased to R150.
The strike began on August 27 last year, and was called off on December 4 and resumed on Wednesday.
Since the strike resumed on Wednesday, De Doorns has been the epicentre of violent clashes between protesters and police.
On Thursday, police used a water cannon, fired rubber bullets and stun grenades in an attempt to disperse thousands of strikers who pelted them with stones.
A truck was hijacked and set alight on Saturday morning.
CCMA offers to intervene
A total of 125 people were arrested between Wednesday and Sunday in connection with the strikes, mostly for public violence.
The Commission for Conciliation, Mediation and Arbitration (CCMA) offered to intervene in the strike on Saturday saying it had the authority and the skills and experience to mediate a solution.
"We have offered our services - which we are empowered to do in matters of public interest - and trust that the parties will respond positively to our offer," executive director Nerine Kahn said in a statement.
The CCMA said they were in a position to mediate a binding short-term agreement while the parties wait for a sectoral wage determination by the labour department.