car is 1990 crx si with zc dohc swap, i just noticed this recently since its been 25 degrees in dallas, we have a 30 min lunch break at work and i went out to get something cause i did'ng bring anything, i had heat full blast and i was freezing cause it was just blowing ice cold air at me and i barely just started to feel any heat coming out right when my 30 min lunch was already over!!! so before clocking out at night i just started my car up 25 minutes before time to leave thinking i can go out to a warm car, but i went out and i did'nt feel any heat at all still, and even after driving home 20 mins later, the heat really never kicked on at all and is worthless. ???

since 1991 the only car i have owned has been a crx and this is my 3rd one and i have never had a n0-heat problem til now, and so i really don't know much about the system and how it works or what i can check to make my heat work and work best it can.

any tips or things i can look at being the culprit???

thanks
-Jon

 

try this. takes 30 seconds to check underneath the heater core.
https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/heat-not-working-2225295/


however i had a slow heat issue and it wasnt that for sure. and i only happened when i was in the mtns last year in the winter (im in socal, only place its ever freezing). unfortunately, i ended up blowing a head gasket in the summer. somehow i had a cooling issue. dont know exactly what the problem was. swapped new engine and its all good.

 

I have a European spec CRX 16v with the DOHC ZC factory engine and it takes about 15 minutes to get the heat going. I would try and make sure that when you operate the cable to the heat instead of cold that the shut off valve on the firewall next to the fuel filter is operating correctly. It may not be opening up far enough to allow coolant to the heater core. Have someone help you by one person turning the temperature control **** and the other person under the hood looking at the shut-off valve.

 

change your coolant.

when i had 70% water and 30% coolant, i was barely getting heat.
when i put 80% coolant and 20% water, it was really hot.
when i put 100% coolant, i was sweating.

thats what i figured out, dont know if this has anything to do with the heater.
i am now i have 60% coolant 40% water, and its perfect.

 

make sure the cable is connected to the valve that lets the hot water flow throught the heater core.its mounted by the firewall.