I need to flush out the heater core in my 98 Dakota.

What is the direction of flow through the heater core ?

Which hose is the IN/OUT ?


TIA

The "IN" hose is the one the comes from your intake manifold. The "OUT" goes to your water pump.

ok, Thank you Sir!

Doesn't matter, you flush in both directions. Flush and more importantly, back flush. Don't go too high with the water pressure.

it's not the use that makes it plugged- it's constantly flowing even with AC on- it's sediment and debris from the rest of the cooling system that gets stuck in the heater core and clogs the flow of water.

Mostly, it clogs when people mix coolants that should not be mixed, or use water with minerals vs distilled.

ie TAP or WELL water. Shops do it ALL the time. Perhaps that's how they get more work.

Funny I have always used just tap water never been a problem.

I'm a fanatic about Upkeep though change out my antifreeze every 3 or 4 years and run cleaner through the system also.