Heater core replacement ?

[sleepertruck72]

I am going to replace my heater core tomorrow because it has a slight leak somewhere. Should I flush the engine with Prestone Flush before or after I swap the Heater core ? I figured before but since it leaks, it may not be a good idea. Its not a leak I can find other than it has stains from behind the lower hose on the heater box. Any suggestions ?

[Stocker]

It's kind of a PITA, at least on an A/C truck... are you sure it's not just a hose/connection problem?

[sleepertruck72]

Stocker,
Mine is non a/c. I should of done this when I put the new engine in. I know the stems are ready to snap off the heater core. I guess I learn the hard way sometimes. I lose quite a bit of antifreeze and I am guessing it happens while I drive because there is no puddles when it is parked. I do get that sweet smell when I stop at a stop sign or parking light and get going again. I usually fill the radiator about once a week depending on how much I drive it. I also will be putting in an overflow tank just to catch any going out that way.