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Q: Anti-syphon device to the tank is not sealed

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The filler neck line in my HHR has a anti-syphon nozzle/valve that goes into the tank. When i put the nozzle back into the tank, it is not a tight fit and I cannot put gas in my HHR due to it not being a secure fit. Is there a gasket or and O-ring or a rubber piece that goes over the opening of my gas tank for the syhon to be sealed completely? Because many mechanics say it shouldn't but there is no way becauee gas shoots out when putting gas in because of the non seal.

My car has 175000 miles.
My car has an automatic transmission.

A: I answered your previous question. You did ...

I answered your previous question. You did not mention that gas was shooting out while filling. This issue is related to another system and does not involve the part in question. When you are filling the tank, the gas you are adding is displacing the air in the tank. This air (that is saturated with gas fumes) has to go somewhere. This is called the evaporative system.

There are several scenarios that can cause your issue. There is a vent (called the vent valve) on the highest point of the fuel tank that serves two purposes. It allows air to leave when filling the tank, and to let air in while the engine is running and consuming fuel. It is purely mechanical with one moving part. It has a caged ball (similar to a wet/dry vacuum) that when you are filling, will float up and seal the vent preventing liquid gas to enter the evaporative system when the tank is full. This could be the problem if the ball is stuck.

Other causes could be clogged or kinked hoses, or a defective vapor canister, or vent valve solenoid. The vapor canister is what the air flows into when filling. It stores the air and gas fumes until the engine is running. It is filled with bags of charcoal. If a bag breaks open, it will clog up hoses and others parts. The vent valve solenoid is a electrical device that opens and closes to seal or vent the vapor canister. It is always in the venting position when the engine is off (when adding fuel).

In summery, the evaporative system will need to be inspected thoroughly. Most of it is accessible without dropping the fuel tank. Also check the filler neck. If no issues are found, the vent valves on the tank (there are 3) are built into the tank and can not be replaced. Therefore the tank will need replaced.

If you need help with getting this fixed, consider YourMechanic, as a certified technician can assist you with these checks and help you repair it as necessary. Good luck

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