mgreene

I have a 1993 civic dx that has a 1.6 vtec engine from a 95 si. I recently replaced the water pump due to a leak as well a the timing belt and water pump while I was in there. my heat went from great to fair. I have went back and changed the thermostat to a 180 degree instead of the 170 factory as well as blowed/flushed out the heater core and checking the mixing valve with no difference. I noticed tonight that the bypass hose that hooks right behind the heater hose on the thermostat housing gets very hot after running a few minutes while the heater hoe only warms slightly. Im getting around 100 degree heat out of the vents but it doesn't seem to be warming the interior of the car nearly as good as before the water pump replacement. Any ideas??

Former User

Do a thorough bleed:

https://honda-tech.com/honda-civic-d.../#post38664177

testify

Depending on where you are, its been extra cold lately.

The heating system in an EG really doesn't run very hot when ambient temps are in the teens and single digits. It's fine in 30+ degree weather though.