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GMC General Truck Fuel Tank Caps
Frequently Asked Questions About GMC General Truck Fuel Tank Caps
Will these fuel tank caps fit my specific GMC General model year?
Our GMC General fuel tank caps are designed to fit most GMC General trucks manufactured between 1977 and 1987. However, there were some variations in tank neck sizes during these years. We recommend checking your existing cap's diameter (most are either 2.75" or 3.5") or contacting us with your VIN number for exact fitment confirmation. Early 1977-1979 models typically use the smaller diameter, while 1980-1987 models generally use the larger size.
Are these caps vented or non-vented, and which type do I need?
This is critical for proper fuel system operation. Pre-1985 GMC General trucks typically require vented caps to prevent vacuum buildup in the tank. 1985 and newer models with evaporative emission systems need non-vented caps. Using the wrong type can cause poor engine performance, hard starting, or fuel tank damage. Each product listing clearly states whether the cap is vented or non-vented. If you're unsure, check your owner's manual or look for emission control stickers under your hood.
What's the difference between locking and non-locking caps, and are the locks durable?
Locking caps provide theft deterrence and come with two keys. Our locking mechanisms use hardened steel components that resist picking and forced removal. Non-locking caps are more convenient for frequent fuel stops but offer no security. The locks on our caps are weather-sealed to prevent corrosion and freezing. Many customers in high-theft areas prefer locking caps, while those in rural areas often choose standard caps for simplicity.
Will aftermarket caps seal as well as OEM, and what about the gasket quality?
Quality aftermarket caps can seal just as effectively as OEM when properly manufactured. Our caps feature automotive-grade rubber gaskets that resist fuel degradation and maintain flexibility in extreme temperatures. Look for caps with thick, properly molded gaskets rather than thin foam rings. A good seal prevents fuel vapors from escaping, eliminates gas smell in your cab, and maintains proper tank pressure. Replace any cap showing gasket cracks, compression, or fuel saturation.
Are chrome caps worth the extra cost over standard black plastic?
Chrome caps offer superior aesthetics and typically feature metal construction versus plastic, providing better durability against impact damage. However, they require periodic polishing to maintain appearance and can show water spots. Black plastic caps are more practical for work trucks, hide dirt better, and cost less. Chrome caps may also get extremely hot in direct sunlight. Choose based on whether you prioritize appearance or practicality for your specific truck use.