I think my heater core might be plugged up... I've never flushed a cooling system before, but I want to give it a shot before I try to replace the heater core.

I'm curious what the best/easiest/cleanest way to flush it would be? I'd like to do it with as little mess as possible.

Also, can someone show me which coolant line I should spray water into that would result in the water flowing the reverse direction of the cooling system...? (I want to see if I can dislodge whatever might be plugging the heater core)

Advice appreciated! Thanks!
--ElmoTheDestroyer

 

You're going to have a real tough time doing this without making a mess. Normally I just find a place where it doesn't matter if I get a ton of water and a little coolant on the ground, disconnect the hoses from the heater core, and cut the threaded fitting off the end of an old garden hose. Clamp the garden hose to the heater core on the side that normally goes back to the radiator, and unleash the flow. This way the water flows opposite the normal direction (backflushing.) When the water through the core runs clear, flush it the other direction, then when that runs clear backflush it again. If water doesn't come through at all, or just barely trickles, the heater core is completely stopped up and it's time to start pulling the dash.

You could try getting about 5" of heater hose to connect to the heater core on the side opposite the garden hose, and run it into a 5-gallon bucket or something to catch the spillage, but I don't know how effective it would be. If the mess is that big a deal it's worth a shot.

 

Right on... The garden hose is a good idea. I can just use the other half of the hose I mutiliate to hook up to the other side of the heater core to direct all of the flushed water to a drain.

Thanks for the tip!
--ElmoTheDestroyer

 

Prestone (and probably others) makes a flush kit...Ive used them before...just cut a heater line and install the T connector to it...then you can do it as often as you need to...

Dunno if this helps your "flush one way and then the other"...but it seems you could get a plug, and just disconnect one end of the T and plug it, to flush one way, then reconnect it, and disconnect the other end, and plug it, and flush the other way...?

Dunno....Im no mechanic...but Ive had good experiences with the flush kits.

 

Depending on how long it has been since the core was flushed you could uncover a leak in the core that has been sealed by sediment. I am not saying don't flush it but just be aware you could uncover hidden problems.

Been there way too many times and had to deal with some pretty PO'd customers.

 

this is a post worth considering. I flushed a heater core on one of my old cars once and it made the heat work much better... but soon after I found that it was leaking inside the car. you may be better off replacing it now

 

Yeh... I've been thinking about that. I'm looking into a replacement core actually. Their cheap, and don't seem to be tooooo awefully hard to replace.

Thanks again for the tips...
--ElmoTheDestroyer