Ok, this will be the third heater core in five years !!! This vehicle is a cream puff 1990 1500 5.7 4x4 with 45,000 original miles and both previous heater cores were factory GM parts. This vehicle was well maintained before I got it and I'm very big on preventative maintenance so it gets regular service including the cooling system annually. My first question is.....is there a better heater core available than the factory part ?? Second, are ther other things, possibly other factors that could contribute to their early failure ? I'm thinking I might have a electrical problem which is causing it to corrode. Any known places to look fot this type of problem ? Third, for similar vehicles that don't have heat, what was used to block the hose fittings ?? How could I just eliminate the heater since I never use it here anyway ? Thanks for any advice.