Can Insurance Companies deny your Insurance Claim if E20 Ethanol Blend Petrol Fuel damages your car? With the government’s increasing emphasis on adopting E20 fuel across the country, many car owners are left uncertain about how it will affect their vehicles and wallets. E20 is a blend consisting of 80 per cent petrol and 20 per cent ethanol. For cars and SUVs specifically designed to handle this mixture, there is no problem. However, prolonged use in older or non-compliant models could result in significant engine damage and, crucially, your motor insurance policy might not come to your rescue.