The car vacuum canister is one of the components of the whole evaporative emission control system that prevents fuel vapors from escaping into the atmosphere. Running from the rear of the vehicle forward, the evaporative emission control system is composed of the gas cap, the gas tank and the liquid/vapor separator which are all located at or near the gas tank. These components are joined by the fuel tank vent line to the components at the engine compartment: the purge line to the carburetor or manifold, the purge valve and the vacuum canister. Installing a car vacuum canister is a relatively straightforward process if you are car repair savvy.
Determine the engine size. Refer to the owner's manual to confirm the vehicle's engine size. You will need this information to order a replacement. Raise the hood of the vehicle and locate the vacuum canister. Look just in front of the front wheel well.
Locate and identify the hoses attached to the canister. Label and tag these lines before removing them. Remove the bolt from the top of the canister. Some models and engine sizes may have the canister held in by brackets.
Lift the canister out of its holding bracket and discard. Set the replacement unit into the bracket. Reconnect the hoses you pulled off to remove the old canister. Replace the canister purge valve. This is an optional part of the process, but it is generally a good idea for optimal functioning: new canister, new purge valve.
Unhook the negative battery terminal. Disconnect the canister's purge valve electrical connection. Label and disconnect the valve's vacuum lines.
Remove the canister purge valve. Install the new valve and connect the vacuum hose after examining it to make sure there are no leaks in it. Reattach the purge valve's electrical connection. Make sure you have a firm reconnection.
Reattach the negative battery terminal. Unscrew the gas cap completely and examine it for any cracks or other damage. Verify that it is the right size and fits correctly and snugly. Screw the cap back into place, being sure to start it straight and turn it until it is tight.
Hook up the diagnostic instrument. Clear the codes the bad canister issued. Test drive the vehicle to make sure no further emissions codes are issued. Monitor the "Check engine" light for new codes for the next few restarts of the engine.
