GMC Jimmy gas leak from top of fuel tank on GMC Jimmy

Some GMC Jimmy owners report experiencing gas leaks from the top of the fuel tank, often due to corroded fuel lines at the fuel pump. A common cause for these leaks is attributed to a leaking fuel line or seal, which may require tank removal for accurate diagnosis. Some owners opt for DIY inspection methods, such as filling the tank until the leak reappears to identify the source. Repair costs for addressing a gas leak can vary significantly, with some shops quoting around $600 for labor to drop and reinstall the fuel tank. Additionally, overfilling the tank can lead to liquid gas entering the evaporative emission system, causing unpleasant odors, so it's advisable to avoid excessive topping off. In some instances, a simple issue like a faulty or improperly tightened gas cap may trigger a gas leak, potentially causing a P0456 code. Addressing these concerns promptly is essential for safety and vehicle performance.