at my work we got a 2007 hlf30 and we got it with 1200 hours on it and with in 200 hours with use the head gasket went. we tore it down and noticed that the head was off it before by someone else before we got it. so we checked the head and it had a little warp so we sent it away to getted milled and we put a new head gasket on and it lasted for about 3 months then we put an other new one in and this one lasted for about 6 months and now is leaking. and it seems to just go. like one day fine the next day steaming really bad. every thing was cleaned and we checked the block for warping to and there was none. we torqued everything to specs to each time. are these motors known for head gaskets? does anyone know what could be causeing these to go so soon? should we be using new head studs? cause that is really the only thing we didnt do? should we use some headgasked shellack? if any one could help out would be great thanks.