The Caltex petrol station on the M4 Motorway where motorists purchased the contaminated fuel. Credit:Peter Rae "We've heard of at least 24 vehicles basically sitting idle on the M4. They broke down. We received about 10 calls from members and we've been dispatching towies out there to get them off the road," NRMA spokesman Peter Khoury said. A Transport Management Centre spokeswoman said the cars were moved swiftly off the road and the impact to citybound traffic had been minimal. Water in petrol to blame Caltex spokesman Sam Collyer said the petrol giant was sorry for the "rare" event that had inconvenienced dozens of customers and many morning peak hour motorists.

He said the company was certain only that the E10 product was contaminated. The E10 pump has since been marked as out of order at the station. Credit:Peter Rae "We quickly shut down the pumps for that product so no other customers will be affected. Our technical team is on its way to investigate what has caused this issue," he said. "Any customers with any problems should hold onto their receipt and call our customer team on 1800 240 398. They will be open from 8.30am this morning." "They are all in the breakdown lanes. Of course some people have slowed down to have a look, but all the lanes are open," she said.

Financial help to be given Mr Collyer said Caltex was prepared to provide financial aid to affected customers. It shuts down the engine and there is nothing that can be done to fix it on the side of the road. We have to tow the vehicles into mechanics NRMA spokesman Peter Khoury

"In the rare circumstances where we do have issues that are caused by our fuel, we'd be assisting them in whatever way, including financially," he said. Mr Khoury said it was most likely water had seeped into the petrol tanks. He said cars would begin to falter and break down very quickly once they had used the contaminated fuel. "What it does is it shuts down the engine and there is nothing that can be done to fix it on the side of the road. We have to tow the vehicles into mechanics." He said fixing the car was usually a costly task.

"It's a pretty big job to clean it. So they have to drain the fuel tank and sometimes that means they have to literally take the fuel tank out of the vehicle to drain it," he said. "They need to drain it, they need to clean all the pipes, they need to replace any of the pistons that have been in contact with the fuel, it may cost a few hundred dollars, maybe more." A motorist named Keith was among the stranded. On 2UE radio this morning, he said he had broken down on the Prospect Highway southbound lane, just off the M4 westbound ramp. "I've just been onto the NRMA. They've just come out, they've had between four and six cars breakdown after leaving the service station," he said, about 5.30am. A witness named Laurie called in soon after, saying: "The cars are about 50 metres apart, with their hazard lights on, all broken down. They had only gotten about half a kilometres from the servo, by the looks of it."

Were you affected? Email ehan@fairfaxmedia.com.au