Do you have to drop the tank replace fuel vent valve on a 1997 Chevy blazer?

No, you generally do not have to drop the fuel tank to replace the fuel vent valve on a 1997 Chevy Blazer. The location of the vent valve varies slightly depending on the specific trim and engine, but it's typically accessible from the undercarriage, without needing to remove the fuel tank. You might need to remove some underbody shields or other components to get to it, but dropping the tank is usually unnecessary.

However, access can be tricky, and sometimes parts of the exhaust system might need to be loosened or removed to gain sufficient access. Consult a repair manual specific to your 1997 Chevy Blazer (year, engine, and trim are important) for precise instructions and diagrams. This will show you the exact location and any necessary steps. Improper access can result in damage, so proceeding with caution and using the appropriate repair manual is highly recommended.