My local mechanic told me to get a new thermostat and gasket, most likley from an isuzu dealer. They told me that thermostat would be $28 & when I asked about a gasket, he at first hesitated then he said another $5.00.. That hesitation seemed kinda strange to me, so I went to Pep Boys & bought a Stant thermostat for only $19.00, & they said that the gasket was included.Is this possible & if so , is the gasket the black ruberized or plastic ring around the back end?....Reason for this is that I have a minor antifreeze leak which only leaks at different times.My mechanic says it may me a back up in the system because only certain hoses where hot while another was cool, so he said that a thermostat and gasket would do the trick. So before I install it I would like to know if he is in the right direction, Thx Bruce