mc

Replaced thermostat
Blower works
Has coolant
Temp control cable isn't broken
Not sure what else to do. It will blow out hot for a few seconds if its been running for a long time but then just blows cool air

HondaPartsHero

Are both heater hoses hot when its reaches operating temperature? If one is hot and the other not you may have a bad heater core. If both are hot you may have a blend door issue inside the car. Also you replaced the thermostat but is the top hot and bottom cold or are both warm? Did you ever bleed the coolant system?

HECTIC

yea i was gonna say a clogged heater core...

92_civic

either the heater core, or its a bad water pump, do you get heat if you rev the motor up? just ran into this on a 99dx coolant had been flushed, heater core checked out, tstat was replaced, pulled the water pump out of it, fins were gone, how many miles on it? has it ever had the tbelt and water pump changed?

B18C5-EH2

WHAT YEAR/MAKE/MODEL IS YOUR CAR?!?!?!

Check to see if the heater control valve works - I'll just show a 1995 Civic since you're not telling us what kind of car you have:



It's on the firewall if you follow the heater hoses back to it. Make sure the cable is connected to it, and that it opens/closes when you turn the temp dial (or slider) inside the car. If it doesn't move then manually move it yourself and see if you now have heat.

JDM4mee

I also have a related question..

In the past, my B16a2 blew the head gasket due over-heating, as a consequence, the old Honda radiator also blew the top cap off, so this was performed to fix the problem:
-milled head
-milled block
-installed ARP head studs
-installed OEM head gasket
-installed OEM radiator
-replaced thermostat with OEM one
-replaced wather hoses (all 5 of them)
-replaced radiator cap with OEM

Everything worked just well until this winter. I notices that temp gauge neddle raises about half way were it should, but when I take the car out on the highway the temp neddle starts to drop until it's about 1/4 of the gauge

What do you guys think about this?

The only odd thing I remenber is that whe I applied the anti-freeze I went ahead I pour a 80 to 20 % (coolant-water)

Could this have been the problem?

jhendry

maybe it really is cooler? more air over the radiator? i noticed that in my yukon xl (i know not a honda) temp was right over 1/2 at the top of a canyon but low rpms and high speed the whole way down to the other side i did notice a good drop in engine temp. i dont know too much just my 2 cents

B18C5-EH2

You should start your own dedicated topic so that the discussion isn't split amongst the OP's issue and yours.

itsnotfast

There are 2 heater core lines entering the cabin of the car as stated above, now when up to operating temperature and heat on blast are both hoses hot? They should be close in temperature not one warm and one hot. If not, you likely have a bad heater core. I know this has been said above, I just wanted to let you know a way to check it.

mc

Car is a 92 Civic DX 235k miles. Motor is a JDM D15B approx 125K Miles.
Coolant system is bled. Heater control valve is working. I even disconnected the cable and moved it manually just to make sure. When car is at operating temp with heat on all the hoses are hot except for the one coming from the firewall to the side of the thermostat housing that one is just kinda warm.

So it looks like a bad heater core. Thanks for all the helpfull replies

delsolo95

theres also another heater control valve at the bottom of the heater core. Passenger side under glove towards the center console.