Walked round the back of my car yesterday and as i walked past the petrol cap i got a strong smell of petrol witch i thought was wierd,went to garage today to fill up and as i undone the cap there was a loud psssst as i released the cap.Does this mean my breather is blocked?? It has never done it before i put an uprated fuel pump in??

 

Mine always hisses as I unscrew it. Nothing major mind, just hiss first turn, hiss second turn, then it unscrews normally and that's it.

 

snakes in the tank, its like snakes in the plane, but with petrol tanks

 

LMAO

 

surely that means the breather is blocked tho dont think its meant to hiss when you take the cap off???

 

My evo's have always done it.

 

My old car(escort gti) and my Golf do that, nothing to worry about

 

Mine hisses on the first sort of two twists of my hand. It don't hiss with the cap off or for prolonged periods of time or for the whole duration of me unscrewing the cap. I've always thought nothing of it.

 

LOL the hiss is normal.

 

Its normal as alex says... normally worse the lower the petrol is though.

 

mine always hisses when low on fuel,the lower the fuel the noisier the hisssss!!!!

 

It's a dump valve in your petrol tank

 

Remember when my ex was filling up her cinq after we had the uprated pump fitted - petrol gushed out like a fountain all over her

Fook i got it in the ear after that

 

when the Cossie conked out of petrol on way back from Nat day, when we got it home and unscrewed cap it made a loud hiss and a booom

must have had a mega air blockage as it seemed as if it was expanding

And the gauge was still reading over 1/4 a tank

 

If the tank has a breather pipe then why does it hiss?? How can it build up pressure if there is a pipe vented to air??