Low heat heater core question

[1badTJ]

Nearly every year I have to flush my heater core to get any heat from my vents on my 2000 TJ. My blend door is functioning as it’s suppose to. I reverse flush it. I switch back and forth on each port trying to break anything loose that might be in the heater core. Each year I put clr in it for about 15 minutes and continue to flush the heater core. My entire cooling system has been changed several times over the last couple years. When I put the engine in I put a I believe it was a Cardone brand water pump because it had a steel impeller. Flushing the heater core helps but it’s still not producing excellent heat. It’s hotter and takes the chill out but it doesn’t get the inside warm enough to make me want to take my jacket off. This is when it’s 32 degrees and below outside. I flushed it again as I’ve done in the past. I pushed compressed air through it to see if I could break anything loose. I then tried blowing through with my lungs. There seemed to be some resistance when I tried to push through with my own breath. Not a lot but some. Has anybody tried blowing through a heater core? I just feel like it should flow as fast and hard as I could push through without resistance. Also when I idle the engine the air cools down some. I have a 195 thermostat. The engine doesn’t get hot when idling nor running down the road on hot days. It might warm up idling with the a/c on when it’s 90+ outside but cools right back down when I start moving or bring the rpms above 1000. I have the 11 blade Ford Explorer fan blade. I can’t help but think that my water pump may not be flowing enough at idle and possibly above idle or there is a plug in my heater core that I can’t break loose. The air gets warmer above idle but as mentioned it doesn’t get super hot inside. Other TJ’s I’ve been in gets plenty warm and can slow the fan down and take the temp off full hot. Thoughts???

 

[kmac5130]

Nearly every year I have to flush my heater core to get any heat from my vents on my 2000 TJ. My blend door is functioning as it’s suppose to. I reverse flush it. I switch back and forth on each port trying to break anything loose that might be in the heater core. Each year I put clr in it for about 15 minutes and continue to flush the heater core. My entire cooling system has been changed several times over the last couple years. When I put the engine in I put a I believe it was a Cardone brand water pump because it had a steel impeller. Flushing the heater core helps but it’s still not producing excellent heat. It’s hotter and takes the chill out but it doesn’t get the inside warm enough to make me want to take my jacket off. This is when it’s 32 degrees and below outside. I flushed it again as I’ve done in the past. I pushed compressed air through it to see if I could break anything loose. I then tried blowing through with my lungs. There seemed to be some resistance when I tried to push through with my own breath. Not a lot but some. Has anybody tried blowing through a heater core? I just feel like it should flow as fast and hard as I could push through without resistance. Also when I idle the engine the air cools down some. I have a 195 thermostat. The engine doesn’t get hot when idling nor running down the road on hot days. It might warm up idling with the a/c on when it’s 90+ outside but cools right back down when I start moving or bring the rpms above 1000. I have the 11 blade Ford Explorer fan blade. I can’t help but think that my water pump may not be flowing enough at idle and possibly above idle or there is a plug in my heater core that I can’t break loose. The air gets warmer above idle but as mentioned it doesn’t get super hot inside. Other TJ’s I’ve been in gets plenty warm and can slow the fan down and take the temp off full hot. Thoughts???

Someone else on this site has pointed out that some heater cores such as the one made by spectra, have a thick plastic turbulator in them. This is like a corkscrew flexible noodle-like thing that sits inside the pipe running through the heater core. It’s designed to create a turbulent flow, which is normally helpful in heat-exchangers like the heater core.

My current heater core is a spectra, and I can tell you that my entire cooling system is very clean and the core is new and all air has been bled from the system. The spectra heater core just does not heat the jeep like the factory one does. You need to get a heater core with a metal spring-like turbulator, rather than the plastic one. Just from looking at a side by side picture, you can tell why plastic blocks the flow and the metal one doesn’t (it’s much thinner). Performance radiator makes heater cores with the metal turbulator. I’m sure other brands do as well, but that’s the only one I am sure of.

Anyway, if I were you, I’d get the performance radiator one and install it. But make sure you have a clean cooling system beforehand. It’s not fun replacing heater cores like you probably know, so you’ll want it to last a while.

 

[Morks]

Just finished my battle with no heat. When I first purchased the jeep, my first vehicle. I had no clue what I was doing and had a shop install a core. The spectra they installed didn't put out any warm air. I flushed the cooling system blah blah. Finally, the spectra broke, put in a performance rad heater core. Definitely gets warm enough, but nothing crazy hot (warm enough today -14 celsius). Then again I have a couple of rust holes that allow a good amount of airflow lol.