Zreiser

I'm pretty sure I need to replace the heater core entirely, but with winter coming on, don't want to be ripping apart the dash and everything involved in the snow. I've seen a few suggestions as a possible quick fix, of just flushing the heater core. I'm wondering, since the heater core runs off the main coolant system, if I (as a quick fix to get me through til spring) can just flush the heater core, run some radiator stop-leak through it (while the hoses are off), let it set, then flush it out again, and top up the system with antifreeze. Any thoughts whether that's going to be an issue or cause problems with the rest of my coolant system? Thanks.

s14unimog

Dude, don't put that stuff in your system; you're not going to fix the leak. Besides, that water is under enough pressure that it sprays out into the HVAC box atomized so it'll be blown out through the vents and leak out of your floor vents. It'll irritate the **** out of your eyes and can't be good to breathe.

My recommendation is to suck it up and replace it or cap the lines. Do not loop the line together b/c it will over heat.

can't you retrieve the heater core from the HVAC box without pulling the dash on a pre-97? I just replaced the one in my 97 and it wasn't too bad. Although I spent an extra day repairing the rust in my floor board from leaky HVAC firewall seals. Search my name for some pictures.

Zreiser

Thanks for the recommendation on the fluids! Definitely don't want to be breathing in those fumes. Haven't seen the heater core replaced on an earlier xj, so I guess I'll keep looking, the only guide I found was on a 93 (but it's pretty much the same I thought). Thanks!

freegdr

most detailed dash removel ive foundhttps://www.cherokeeforum.com/f51/dash-removal-35444/

DFlintstone

Years ago maybe 5, my core started a small leak, stank, fogged up the windshield. I put in one or those small canisters of aluminum looking powder, Alumaseal was a brand name. About the diameter of a quarter and 3 in long. Maybe I got lucky, it's fine to this day. You want to go for a good long drive after you add it. It will settle in low flow places like back around #6.

I don't trust the heavier stuff like BarsLeak not to plug something I'd miss.

To back-flush, don't use full house pressure. I hold both the hose and the garden hose in my hand and squeeze. Go back and forth, both directions.

I don't see you having much luck trying to get it to plug up like you suggested. I think it takes time under pressure. Maybe you could invent a machine! Like a hart pump. There in Salt Lake, serve coffee while you "service" the skiers heaters!

sonicsix

Just had this issue with my '99. Had originally disconnected the lines and connected them together to bypass the heater core. It never ran hot, either. Ended up buying a new core with plans to install it but decided against tackling that job myself so I returned it. I went to the local radiator shop and had them flush the cooling system (since it was due anyway) while the heater core was still disconnected. I used a garden hose and flushed the heater core myself, both directions several times. I picked up some new heater core hoses and installed them along with a jug of Aluma-Seal (from the people who make Sta-Bil). It fixed my heater core leak.