Hey all in preparation for winter I decided to finally flush my heater core, thanks to the good redneck ideas contained herein:
http://www.youtube.com/watch?v=mMp82zLVxoU

What a difference! I had recently flushed and replaced the rad coolant, which is bright green and healthy looking, but what came out of my heater core resembled a chocolate milkshake. The bleach and subsequent 5 hot water flushings really got it clean. I suspect that there was absolutely no coolant transference before cause the heater would not get hot at all, now my heat is super hot, my in-dash thermometer needle doesn't jump all over the place while driving, and my engine temp stays a solid 5-10 deg cooler (as per aftermarket under-dash thermometer).

Thanks Davesfarm!

 

cool... Did you cut your hose or pull it from the heater core?

I'm due for a flush

 

Mine had already been spliced with a nipple, so I just undid that and went to town. The inlet hose running from the engine was easy enough to access with only a moderate amount of fluid loss.

Even tho it has been pretty warm these past few days in N Florida, I still turn the heater on and marvel at how hot it gets. Its nice to have defogging functions returned as well.

 

swap, I did a search on the forum, and you post of a couple years ago came up. I need to do a total radiator/coolant and now maybe a heater core flush too. The youtube video you posted is no longer available. Can you please go into a little more detail for me about how you did the heater core flush? You mentioned using bleach - did you have the Prestone adapter valve already connected to the heater hose? The heat on my '93 3.9L hasn't been getting for some time now, and I wonder what kind of gook will come out - definitely needs a good cleaning! Thanks!