Fuel Tank Overpressure?

[pishta]

My wifes 91 LS400 gets a hesitation every now and then and she swears that venting the gas tank by loosening the filler cap fixes it. I have done that too and was suprised by how much pressure builds up in there. Is the vent in my cap malfunctioning or is the vent in the tank? If you unscrew the cap like you are going to gas it up, itll "exhale" audibly for about 4 seconds. Is this normal?

[pishta]

My wifes 91 LS400 gets a hesitation every now and then and she swears that venting the gas tank by loosening the filler cap fixes it. I have done that too and was suprised by how much pressure builds up in there. Is the vent in my cap malfunctioning or is the vent in the tank? If you unscrew the cap like you are going to gas it up, itll "exhale" audibly for about 4 seconds. Is this normal?

reply

[eatingupblacktop]

Prob just need to replace the cap gasket:

http://www.lexls.com/tutorials/maintenance...lcapgasket.html

[jcrome04]

Oh hey while on topic...

what's the part number for the gasket for a 97?

[pishta]

Prob just need to replace the cap gasket:

http://www.lexls.com/tutorials/maintenance...lcapgasket.html

What exactly does the gasket do , vent pressure at a certain point?

[eatingupblacktop]

Prob just need to replace the cap gasket:

http://www.lexls.com/tutorials/maintenance...lcapgasket.html

What exactly does the gasket do , vent pressure at a certain point?

I think you're right. It seems to me that it would function much as a relief valve, contolling pressure buildup, especially during the summer heat.

[jcrome04]

Would this be it?

#7: Filler Cap Gasket??

http://www.parts.com/oemcatalog/index.cfm?...playCatalogid=0