October 26, 20141 found this helpful
What I normally do is buy two flush kits that you can normally get at walmart or you auto parts store. I hook the "T" connector to both hoses going to the heater core in the engine compartment. I personally try to hook my Jose up to a hot water source, I also like to pour coolant flush into the core prior to flushing to help break up any gunk.
Also you want to punch off the hose on opposite side of "T" connector to force the water towards the heater core and not the toward the engine as this can mess up the thermostat and make sure that the second hose coming from core can dump into a container and is not attached towards motor or the gunk that will break free can go into motor and cause damage.
I've done this a hundred times and have saved tons of money from having to replace heater core. Total cost with new antifreeze and two flush kits should be around $30 rather than $400 for new heater core and $1500 for labor. It's definitely worth doing. You can also find videos YouTube and other sources (some prefer to use compressed air rather than water).
The only time you really need to replace heater core, is if it is leaking which in this case, your passenger side floor will most likely be wet).
October 26, 20140 found this helpful
It sounds like your heater core is clogged.. It's usually very expensive and time consuming to repair a clogged heater core. It usually involves taking your dashboard off on the passenger side to get to the core... I would recommend getting a flush kit from your auto parts store (I usually get two) and where the hoses go to the heater core in the engine compartment, hook the flush kit up to both hoses coming from the heater core and flush it in both directions.
I usually try to hook my hose up to hot water to help break any gunk loose. You might also try pouring some coolant flush in prior and let sit to break up any gunk before flushing.