Hissing from front of car after use

1. Harv Saxperience Forum Bum Joined: Mar 2007 Mold Posts: 2936 EP3 Civic Type R

   #1 23rd March 2011, 20:13

   Recently my car has developed a hissing noise when the car has been used and turned off. Lasts around 30 seconds or so then goes off. Temperatures are fine when driving, even when giving it some stick - it always stays just below halfway.
   
   Any ideas? I'm hoping its not the bloody head gasket! No water seems to be being used and oil cap is fine.
   
   Thanks
2. malcanator L-plater Joined: Nov 2010 Posts: 47

   #2 23rd March 2011, 23:49

   Check the pipe that goes from the plenum to the brake servo, there isnt a clip on them and they can work loose, it could be you are loosing vacuum pressure.
3. Oc2 Frequent Poster Joined: Apr 2010 Nottm. Posts: 924 Focus ST2 ASBO

   #3 24th March 2011, 17:51

   I get this, as i posted in another thread about water
   
   mine comes from the cap at the top of the headertank, like its boiling water but the water never gets any lower, just undo it but keep pushing it down, then gently lift it up and youll hear the air escape
   
   My temps hit just over half way, but i get this even under half way