I’m doing diagnostics on the car while it has low or almost no heat at all. Flushed the heater core and there was heat only for a few days. I’ve heard that door bend is a common issue with Honda but it moves up and down while I adjust the temperature gauge. I’m thinking about the evap sensor but I can’t find the location and how it looks like with Google. Please help!
You should check the thermostat to see if its opening.
Causes include bad or missing thermostat, low coolant, poor coolant circulation due to weak pump , plugged heater hoses. Plugged heater core. Does your temp gage rise at normal levels? If so check temperature of heater hoses when car is hot, running and heater is on. Both hoses should be hot. If radiator hoses are hot and heater hoses are not then heater core is probably too plugged even for a flush to clear.otherwise could be air in system
I checked most of the causes above but haven’t found out yet. 2 shops were unable to diagnose the problem. They suggested replacing heater core while it was done by my friend’s shop
If flushing the heater core helped for a while, maybe just flush it some more. Try reverse flushing, so the flushing flow goes in the opposite direction the heater core normally operates. If you got good flow through the heater core and the incoming coolant is hot (on the order of 190 degrees F), but no heat comes out into the cabin either an airflow door isn’t oriented correctly, the blower motor/fan isn’t working, or the heater core is kaput. Beyond that, if you just want it to work, removing the heater core and taking it to a radiator shop is probably the best first step. That can be a very big job though.