Purpose of Fuel Tank Filler Flap ?
#1
02-28-2016, 12:37 PM
Purpose of Fuel Tank Filler Flap ?
So here is an almost trivia related topic.
What is the purpose of the fuel tank filler flap ?
Clearly not to seal for emission purposes, not much of a hindrance to siphoning, not much help in sealing in case of a rollover (and many cars have a check ball valve for that purpose in addition to a "flap"). So what is it for ?
In the case of GM cars, the flap is eliminated on cars and trucks (most anyway) aince 2006 to 2008 or so, and GM issued a TSB explaining that the flap was previously used in combination with the plastic insert of the required filler diameter in order to ensure that the fuel nozzle was grounded to the chassis and eliminate the chance for static discharge. The TSB goes on to explain that the flap was eliminated in favor of an all metal design of the filler pipe no longer requiring an additional grounding point.
So why then does Jaguar (on the earlier models for sure) and also BMW use a flap with an all metal construction that should not require the additional grounding for the filler nozzle ?
Here is an example of a newer GM filler with no flap.
What is the purpose of the fuel tank filler flap ?
Clearly not to seal for emission purposes, not much of a hindrance to siphoning, not much help in sealing in case of a rollover (and many cars have a check ball valve for that purpose in addition to a "flap"). So what is it for ?
In the case of GM cars, the flap is eliminated on cars and trucks (most anyway) aince 2006 to 2008 or so, and GM issued a TSB explaining that the flap was previously used in combination with the plastic insert of the required filler diameter in order to ensure that the fuel nozzle was grounded to the chassis and eliminate the chance for static discharge. The TSB goes on to explain that the flap was eliminated in favor of an all metal design of the filler pipe no longer requiring an additional grounding point.
So why then does Jaguar (on the earlier models for sure) and also BMW use a flap with an all metal construction that should not require the additional grounding for the filler nozzle ?
Here is an example of a newer GM filler with no flap.
Last edited by 64vette; 02-28-2016 at 12:58 PM.
#2
02-28-2016, 03:06 PM
From the GM TSB:
"
New Metal Fuel Filler Tubes Without a Flapper Door
A revised style offuel filler tube has changed materials from plastic to metal construction. Onplastic fuel filler necks, the metal flapper was included as a safe dischargepoint for static electricity. With the metal style of fuel filler tube, theentire neck serves as the static discharge point making the flapper redundant.Important: Do Not attempt to change the fuel filler tube because the flapper isnot present. Replacement fuel filler tubes will not be equipped with theflapper. "
"
New Metal Fuel Filler Tubes Without a Flapper Door
A revised style offuel filler tube has changed materials from plastic to metal construction. Onplastic fuel filler necks, the metal flapper was included as a safe dischargepoint for static electricity. With the metal style of fuel filler tube, theentire neck serves as the static discharge point making the flapper redundant.Important: Do Not attempt to change the fuel filler tube because the flapper isnot present. Replacement fuel filler tubes will not be equipped with theflapper. "