Hissing from fuel cap
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Lilhas123
- Posts: 2
- Joined: Wed Mar 29, 2023 2:49 pm
- Location: Warwickshire
- Qashqai Model: Mk.2 Qashqai Facelift - J11b (2017–2021)
Hi, picked up my 2019 Tenka early 2 weeks ago. When I pull up at the filling station and release the fuel cap there is a large intake of air into the fuel pipe. Is this normal?
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gloucester
- Posts: 5197
- Joined: Sun Apr 03, 2016 7:04 am
- Location: Gloucestershire, England
- Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)
Welcome to this forum.
That happens on many cars in my experience.
That happens on many cars in my experience.
(2015 Nissan Qashqai Tekna DIG-T 1.2 sold 15/6/18) ~ 2018 Suzuki Ignis SZ5 - 2018 Yamaha MT-07 ~ (2024 Volvo EX30 ordered)
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Qashowner
- Posts: 564
- Joined: Wed Apr 17, 2019 10:07 am
- Qashqai Model: Mk.2 Qashqai - J11 (2013–2017)
Are you saying you have negative pressure in your fuel tank, and air is going into the tank when undoing the fuel cap? If t is, I would worry a little. If you went on a long journey and air was not getting into the tank you would create a vacuum and then it's a battle between the fuel pump and the vacuum to deliver the fuel to the injectors. I would suggest you may have a blocked breather.
One of my old bosses had a new company car in 1973 a MkII GLX 2 litre Cortina in the days of the 6 day war, no fuel and lots being syphoned. He bought a locking fuel cap and low and behold the car would just stop, leave a few minutes and easily start again and then stop. On the old carb cars the fuel starvation caused by a non vented fuel cap starved the engine of fuel and was directly caused by no air getting into the tank to replace the petrol exiting the tank causing the vacuum.
Just recheck it is not air exiting the tank, some system work on a slightly pressurised system, none, as far as I know work on a negative pressure system.
One of my old bosses had a new company car in 1973 a MkII GLX 2 litre Cortina in the days of the 6 day war, no fuel and lots being syphoned. He bought a locking fuel cap and low and behold the car would just stop, leave a few minutes and easily start again and then stop. On the old carb cars the fuel starvation caused by a non vented fuel cap starved the engine of fuel and was directly caused by no air getting into the tank to replace the petrol exiting the tank causing the vacuum.
Just recheck it is not air exiting the tank, some system work on a slightly pressurised system, none, as far as I know work on a negative pressure system.
Past cars Mercedes B Class, S Class, E Class Estate, E Class Coupe, G Wagen, 260E interspersed with Peugeot 406 and Audi Coupe.
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QashqaiSilver
- Posts: 275
- Joined: Sun Jan 09, 2022 10:35 pm
- Qashqai Model: Mk.1 Qashqai - J10 (2006–2013)
My J10 was doing this a lot when I bought it. When you fill it up, do not do it past the click. It took some months for it to stop doing that, the X-Trail I had also did this.
Never happened on my mk2 Focus as that has the easy fuel without fuel cap. My VW Tiguan it never happened to either. It used to happen with my mk5 Escort I had years ago, but nearer the end it stopped. Same goes for the Nissan Cherry I had.
I think before as I never used to fill up to full, or if I did I really used to brim it till it went out the overflow
Never happened on my mk2 Focus as that has the easy fuel without fuel cap. My VW Tiguan it never happened to either. It used to happen with my mk5 Escort I had years ago, but nearer the end it stopped. Same goes for the Nissan Cherry I had.
I think before as I never used to fill up to full, or if I did I really used to brim it till it went out the overflow
J10, 2008, 1.6 petrol, Acenta
