Okay, I really, really, really need heat. It's not totally unbearable, but it sucks.
However, I don't want to pay $500~ for a shop to replace the heater core, and I definitely don't want to do it myself, interiors and me = no good. Besides, in 2 months it'll be in the 90s again, so it's really a useless endevour.
So I was thinking, is there any way I could use a radiator stop leak in my heater core? I've heard that stuff can mess up radiators, so I'd just put like 2 bottles into the upper heater core hose, let it chill there for a while, then fill it up with water, wait a few hours, then flush it all out and let it sit overnight and "dry" in hopes that it will fix the leak?
It is a safe bet that if you did that, yes it would fix the leak, however, I can assure you that you will have little or no heat, because your heater core will be so clogged with gunk that you will not get good coolant flow through it, and poor heat transfer.
98 TJ Street Sleeper- 408ci Stroked Magnum V8
Alright, I used the stop-leak, and it stopped the leak...
But heat is still a negative.
Now I noticed my coolant temp never reaches 210. Even with AC on, idling, in the Florida heat.
It stays at about 200-205. Even drove it around at 4000 rpms, didn't move. Also, my upper radiator hose never gets pressurized, and my heater core hoses aren't even getting warm (neither of them). They were "warm" before I did the stop-leak, but now they're almost cooler than the outside air.
I would check the thermostat, and then have it completly back-flushed. You can back flush it when your thermostat is out by hooking a hose up to the line going into the thermostat housing. This will get all of the crap out of the block and should get it out of the heater core as well. Otherwise, get a prestone back-flush kit, it makes it really easy to do. BTW, do you use coolant or just water in your system?