Lower Radiator hose is cold and blowing luke warm heat

buckwheat

New Member
I have a 1997 Honda Civic EX with a D16y8. The upper radiator hose is hot and the lower hose is cold. The thermostat was just replaced. I flushed the radiator and the heater core. My car only blows luke warm air at full temp. Just wondering what you guys think i should do. I have bleed the cooling system. In a few weeks i will be replacing the timing belt and installing a new water pump at the same time (198,000 miles) and sense i am draining the coolant i am flushing the block and cooling system. Do i need a new radiator or heater core?
It would be nice to have decent heat in my car again. Any help is appreciated.
 

RonJ

Banned
Describe exactly how you bled the cooling system.
 


buckwheat

New Member
I took the radiator cap off. Turn the car on with heat all the way on hot and fan on 4. I run it like this until car reaches correct operating temps. Fan kicked on and waited a few more mins Also, I squeezed the hoses like people have suggested. filling it to the radiator neck.
 

Wreckless Hype

¯\_(ツ)_/¯
Registered VIP
5+ Year Member
RonJ has the greatest advice ever given, "Don't guess, troubleshoot", save yourself the time and money. Unless you're absolutely positive it's a water pump, don't touch it. That's a whole new can of worms there. There's a lot of hoses in the cooling system and if your car is warmed up, squeezing a couple or even just feeling the temperature can give you an idea of where the hang up is.

There's several around the thermostat housing, there's two going to your heater core, obviously your two radiator hoses. If you grab the feed for your heater core and it's warm, but your return feels like there's a lack of pressure or cool to the touch, you likely have some blockage. If it's not leaking, you can likely just put a garden hose up to you to clean it out. Worked for me, blew a lot of crud out.

Also, while you're running it after bleeding the system and refilling it, make sure you're checking and topping off the coolant.

If you're fan is not kicking on at all during this process, you need to find out why.
 

buckwheat

New Member
No I don't think you are trolling me RonJ. From what I hear you are the go to guy on this forum and I value your input. You know your s**t!! I'm just trying to figure out this problem, winter in North Dakota sucks and its cold as hell. I will try to bleed it again and put the front of the car on ramps or the 2 post lift, and go from there. If it is bleed properly and I still have the same problem what else do you think it could be? I have heard that it could be a blockage in the radiator or heater core. But I flushed them less then a year ago. (don't mean that the flush worked) While it is in the shop it blows decent heat, but when I take it outside its back to luke warm heat.
 

fabricgator

FabricGATOR
buckwheat said:
No I don't think you are trolling me RonJ. From what I hear you are the go to guy on this forum and I value your input. You know your s***!! I'm just trying to figure out this problem, winter in North Dakota sucks and its cold as hell. I will try to bleed it again and put the front of the car on ramps or the 2 post lift, and go from there. If it is bleed properly and I still have the same problem what else do you think it could be? I have heard that it could be a blockage in the radiator or heater core. But I flushed them less then a year ago. (don't mean that the flush worked) While it is in the shop it blows decent heat, but when I take it outside its back to luke warm heat.
Click to expand...
Its just cold outside. :P
 
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