99 xj sport heater core
 

I'm pretty sure I have a lead on my heater core. Windshield fogs easily near defrost vent and slight foggy mist coming from heater vents when the heat and air both off.

Was wondering if any risks involved with bypassing the heater core if I don't need it? I know the heater core acts as a small radiator, but bypassing it shouldn't cause issues with overheating, right?

Mine started leaking last spring. I bypassed it by unhooking both hoses, rerouting them into abig loop, and using a straight plastic tube from autozone with 2 hose clamps. Didn't have any issues all summer, then reconnected it when I replaced the core in the fall.
Be ready for a big job. I took all the stuff apart, taking picts with every piece, so I knew which peice to put on next, when I reassembled it. Took an evening to take it apart, and 1 to put it back together.
You DO NOT have to take out the whole dash, unhook it all, and swing it out of the way from the passenger side {where the core is}. If you pull the whole thing, you have to take off the steering wheel, which is harder. I held back the dash with a bungee cord hooked to a belt around the driverside headrest.
Good luck.

Sweet...what year model is yours? The general consensus seems to be it is fine to bypass.
BTW..nice engineering on the bungee trick.

98-check the profile by my pict. Just bought another a few months back.

Another of the issues is that you'll have to drain/open the AC during replacement... look on youtube for some videos. Also, there are some nice writeups on the forum.

I HAD to change mine, I live in Detroit. If you live where it's warm, bypass it, and forget it. Good luck-

Oh why the ac drain? Does bypassing the heater core effect the ac at all?

Also where do you make the "loop"?

Ac condenser is in the heater box with the heater core, if the ac lines arent disconnected you can't get the heater core out.

It's a fun job, took me 6 hours last time I did it, I could probably cut that I half now.

When you unhook... or just plain cut, the hoses from the heater core connections on the firewall, loop both of those ends together with a plastic peice of pipe that fits snugly into them, end to end. You should be able to cut off a small piece with a razor knife {a little loop} and take it with you to the autoparts store. Tell the guy at the counter wht yu'r doing, and he'll give you th right stuff.

It's important to "loop" it so that there aren't any kinks in the hose, restricting flow.

It doesn't generally matter where the loop lays, so long as it's not on something hot.

The only thing hot enough to melt a heater hose is the exhaust manifold on the other side of the engine.

A kink in the heater hose isn't going to cause an issue either.

Thanks for the info. I picked up one of these Dorman Heather hose connectors. 5/8 to 3/4. Should work just fine, right?

http://www.autozone.com/autozone/acc...er=102831_0_0_