Looking for some help with my 92 Accord. I've been without heat for about a year now. I've finally devoted a day to try and resolve the issue.

I don't recall when the heat stopped working but, in the last 18 months I replaced the radiator and rebuilt the motor. About a month ago I replaced the thermostat with an OEM one thinking maybe the Stant one was junk. The issue remains, I appear to have a small leak along the back of the block where the water tube seals by o-ring. The leak doesn't appear detremental to the volume of coolant in the system so I haven't considered this to be the culprit. I verified all related fuses are in tact, ventilation routing is clear and vent doors are operational. The valve on the firewall is also working. In attempt to unclog, I removed the heater core hoses and forced air from my compressor through the core. Fluid came out but I have no way of measuring the volume flow rate or how to compare it to ideal.

Prior to rebuilding my engine I had used Bars leak to seal a suspected head gasket leak. Does anyone know if Bars leak could clog a heater core? My heater core does not leak but I am considering replacing it because I don't know what else could prevent my heat from working.

I currently have the AC box beneath the dash removed. This was my first step to replace the core. Before proceeding any further I searched H-T for helpful threads. It seems I have confirmed the need to remove the entire dash to replace the core. I've removed a dash once before and it's a PITA. I'm thinking about refilling the radiator, turning the car on and placing my hand on the heater core I've exposed beneath the dash. If the flow is unrestricted it should surely become hot to the touch.

Any other advice is welcome!

 

I ran my car for about 15 minutes and then put my hand on the exposed heater core. I could feel heat but it wasn't so much that I couldn't stand the heat. Next I decided to remove the AC core since my AC didn't work anyways. I reassembled the vent system and restarted my car to find no change. I still think maybe the core is clogged and not enough coolant is circulating. Otherwise, I don't understand why I don't have heat.

 

Definitely.

Adding that crap into your cooling system is a sure-fire way to cause problems later on.

 

Did you use water from a hose after using an air hose, If no I'd try water pressure first before ripping apart the dash. You can use bleach or other chemical substitute to help flush the heater core, let it sit for a awhile

There's a guy on YouTube that demonstrates this, he did;t use bleach he used another chemical. Type ericthecarguy.com, he has his own site as well as YouTube.

Try the water pressure (if you haven't) first with some kind of chemical, if no luck then go ahead rip apart the dash.

 

I didn't do a comprehensive back flush with water or otherwise. So I watched the video you recommended. It looks like it's worth a try before I go through the agony of pulling my dash out. Thanks for the recommendation, I will let you know the results!

 

Sorry for the delayed response, I finally had a chance to perform a solid back flush. I am blown away by the results. My heat works like new again! I followed the ericthecarguy method using CLR solution.

Thanks kidcool1977!

 

No problem I'll do it myself when this damn weather warms up, my heat is luke warm not toasty warm as it should be.