Droppin the Mrs off the othernight herd a buzzing/whizzing noise. thought it was jus fan on but when i got hime looked into it opened bonned couldnt really hear it. closed bonnet put head neat passenger wheel could hear it a bit. walked to back of car could hear it alot more. stuck my head under the read end and sounds like its coming from top of petrol tank?? has anybody had this problem before? it doesnt always do it like the pump working away louder than its meant to