NIsmo85 Posted April 2, 2015 Posted April 2, 2015 Afternoon all, My car has developed a hiss when I remove the petrol tank cap when I refill. Any ideas what could cause this? It hasn't always done it. Cheers. Quote
RobPhoboS Posted April 2, 2015 Posted April 2, 2015 My one does this, always has done, typically when warmed up and running down a bit. 2 Quote
GIXXERUK Posted April 2, 2015 Posted April 2, 2015 it's normal, maybe temp related or the amount of fuel remaining in the tank ? Quote
GIXXERUK Posted April 2, 2015 Posted April 2, 2015 My one does this, always has done, typically when warmed up and running down a bit. it's normal, maybe temp related or the amount of fuel remaining in the tank ? 1 Quote
ts743 Posted April 2, 2015 Posted April 2, 2015 It happens on all cars with catalytic converters - the fuel system is lightly pressurised. Quote
RobPhoboS Posted April 2, 2015 Posted April 2, 2015 It happens on all cars with catalytic converters - the fuel system is lightly pressurised. No cats here. Quote
-Bradders- Posted April 2, 2015 Posted April 2, 2015 It happens on all cars with catalytic converters - the fuel system is lightly pressurised. No cats here. did have originally though. Mine does this too, especially if I've been cornering hard lol Quote
jimboy2 Posted April 2, 2015 Posted April 2, 2015 Bet you feel good now. What you thought may be a issue turns out normal! Now get back in and drive some more! Quote
ilogikal1 Posted April 2, 2015 Posted April 2, 2015 It's to reduce fuel vapour emissions (along with carbon canisters). Most vehicles now run the tank at a negative pressure stop fuel vapour venting to atmosphere since the regulations were changed in 1998 (ish... I think). Quote
CJRamze Posted April 2, 2015 Posted April 2, 2015 The 350s hiss is far louder than any car I've owned before but its normal Quote
Stutopia Posted April 2, 2015 Posted April 2, 2015 Mine used to hiss all the time, hasn't the last two times... This feels EXPENSIVE already Quote
tatooandy67 Posted April 2, 2015 Posted April 2, 2015 Nothing to worry over, mine hisses sometimes when I undo the filler cap, seems to be more so when the level in the tank is low 1 Quote
Ricey Posted April 2, 2015 Posted April 2, 2015 It's to reduce fuel vapour emissions (along with carbon canisters). Most vehicles now run the tank at a negative pressure stop fuel vapour venting to atmosphere since the regulations were changed in 1998 (ish... I think). Purge canister Reroutes the gases back into the intake. Quote
nissanjuke Posted April 2, 2015 Posted April 2, 2015 mines does this too we all have something in common the dreaded Z bug Quote
Matt_182 Posted April 2, 2015 Posted April 2, 2015 I take it as a sign that it's gasping for more fuel! Quote
JetSet Posted April 3, 2015 Posted April 3, 2015 seems to be more so when the level in the tank is low Yes, both of ours really suck the air in when it the DTE reads ---. Hardly makes a sound if you've already got £20 of fuel in it. Pete Quote
chips Posted April 3, 2015 Posted April 3, 2015 har har! I've always wondered about this one but never been too worried about it, nice to know but so thanks for the answers. My bike also does the same big gasp also when I open it and it's only a 15l or so tank. Explains it as my top up routine is to do it when fill light flashes or shows '---' 1 Quote
Tay Posted April 4, 2015 Posted April 4, 2015 Hissing is normal, i always fill the tank from near empty and I've never known it not to hiss. And its not a hiss, it shows your car is alive, its actually a big sigh from the car as she is saying 'finally going to get my thirst quenched' Quote
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