Drivers with certain motors are being warned that they should check if their car is compatible with the new E10 fuel.
The petrol will be introduced in UK petrol stations in September but is already being rolled out in certain forecourts.
Some cars that are older than 2011 may be at risk of damaging their vehicles or even voiding their insurance.
It is expected to affect a million cars across the country, Birmingham Live reports.
There are a number of ways that owners can check if their cars are affected by the change.
One of the ways is by using the Govenment's E10 checker where you put in your licence plate which tells you if your vehicle is not compatible.
However, according to the RAC, there will be makes of cars that will not be compatible with the E10 petrol and users should be made aware of them.
10 models that will have the most registered E10-incompatible cars in 2020, according to the RAC Foundation (number of cars in brackets):
1. Volkswagen Golf (28,066)
2. MG MGB (20,890)
3. Mazda MX-5 (18,162)
4. Nissan Micra (15,785)
5. Morris Minor (12,796)
6. Rover 25 (9,879)
7. MG MGF (9,352)
8. Ford Escort (8,947)
9. Rover Mini (7,614)
10. MG TF (7,568)
Malcolm McKay, spokesperson for the Historic and Classic Vehicle Association, warned it was not all bad news.
He suggested E5 fuel would likely be available “for a while” due to the popularity for higher octane fuels.
He said: "It certainly hasn’t had as much publicity as the change from leaded to unleaded fuel.
"It's another of those things, I think that the classic car movement to an extent have been scared to make too much of a fuss.
"We’ve just got to find a way around it.
"E5 is still going to be available for a while but it's more a case of the Government has said it can be available.
"It’s then up to the oil companies and the suppliers to decide whether there is enough demand.
"But as it’s the higher octane fuel and there's quite a lot of younger cars that run a lot better and more efficiently on the higher octane fuel I think we will see it around for quite a long time.
