1.9 TDI injector

[bez101]

i know f all about oil burners
mt T plate 1.9 TDI red I A4 B5
when its started it makes a put put sound if i put my hand over the injector the 1 nearest the windscreen back 1 i can feel air
its not leaking diesel and car runs good
is there a seal or O ring or anyone know what it could be ?
TIA

[Alan02]

Its your Injector Heat seal blowing past.Its a metal seal that sits between the head and the injector.You will need a deep 27mm socket to remove it.Its a quick and easy job to do.Dont overtighten the injector on refitting,including the inj.pipe.Should be penies to buy.