As mentioned above,the o-rings retain pressure in the system..Not havin the cap on will not cause it to leak,the o-ring prob is shot 
__________________  2006 GMC 2500hd4x4SLE cc/sb...LBZ
HIFLO exhaust.  & ''HP enhancers''..... 
2002 GMC ex cab/5.3/98k
1987 Monte Carlo SS 82k
1978 Malibu[2dr.350ci/TH-350..ME built
2002 YukonXL[work rig!]319k**5.3/Hypertech'ed The left lane is built to pass,move or we'll run over yurassss!!!!
Kevin
FORSHO[Tm]......
There,it's offically patented....LOL |