Cliff notes before anything! I think my heater core is leaking internally, I heard gurgling inside the car.

Figured I'd post a problem I am having, or was having.
I have been having issues with my coolant disappearing since last summer. I corrected problems with heater hose clamps and the missing coolant would become less frequent, but ultimately would come back AKA that coolant light! After a long day of driving and no problems, I figured it just went away. Blast! I'm idling at a red, and the ******* light came on! FUUUUUU
Once I was moving again, the light went off and I eventually arrived home. I shut the car off and finally heard the problem. The heater core inside was making a gurling noise. You could hear there was air inside. Where there is air, there is a leak. BUT! During all this, I had the logicon slider all the way to max heat (though the fan never on). The next time I took the car out I refilled the little bit of missing coolant and bled the system properly. I also put the logicon all the way to max cooling knowing at the very least I was not in "heating mode". It has been like this for a few hundred miles and A LOT of idling time. The coolant is not disappearing, the light is not coming on, and the gurling is gone. I haven't had any problems in a while.

The problem is somewhat solved. I'm afraid that if I turn the heater on though the problem will come back. I do NOT want to replace that heater core.

The problem went away when I simply put the logicon to cold 1 month ago. No more gurgles, no more missing coolant.

It has to be the heater core, right?

 

If the core is leaking, you should have some soggy carpet. I had a tiny hole somewhere in my heater core, and it ended up soaking my interior. Why don't you pull the core and look for dried up coolant? It's really not that hard to remove/replace one. There's a cover that you access from under the driver-side of the dash. Take it off, and you'll see the core and its 2 hose connections.

 

I figured since my leak must be slow, the carpet must be drying off before I could notice. Also I actually don't drive much, so not much would be coming out to begin with. Hence, I could never truly pin point it.

You are saying I don't have to remove the dash to get to the core?

 

if you do not want to replace the core I would by pass the lines, I would not just leave the slider on cold

 

For now the slider on cold seems to make a difference... or maybe it's all in my head. But the problem has not shown up since I've done that. I'd bypass the lines as my absolute last resort. I like stock functionality. I'll have plenty of time this summer to fix things.

 

I have had a heater core let go while I was driving, it aint pretty.

Never in a FC but in other cars its a ******* mess and it sucks, the smell never gets out

 

Just figured i'd also mention why anyone should keep it. I just took the car out for a spin/get gas and it started to rain. I closed my window and.... the windshield completely fogged up. While it's warm out, you still need to blast the heat on the window to get rid of that fog. Definitely want to see out of my car if it's raining out! Granted, driving a modified turbo rotary in the rain is not a good idea.

 

rain x the inside of the windshield and carry a towel

I agree a heater core is a good thing to have, but not one with a issue, if you really want to keep those windows clear get the AC working!

 

Yeah, the heater core can come out without disassembling half the car. Bypassing the whole thing with a piece of metal tubing and a couple clamps can work, but the heater can be so nice to have. I bypassed mine in this way for a long time after the leak started, but then eventually realized how simple it was to get at the core. I never found the leak in the old one, but once I popped the new one in, it all went back to normal.