Civic 2004 EX - Heat not hot enough

[thecca]

Hi. I just bought a 2004 Civic EX 4 door with the Vtec engine (D17). I took it for a ride (fully warmed) and noticed there weren't as much heat as it should be.

Let's say that the blown air is warm, but not hot

I've checked the coolant, no bubbles or so. Let the car run until operating temp (the gauge sits before the middle point) and does not overheat.

I've read that it could be plenty of things... Clogged heater core, thermostat issue, etc.

Since it does not overheat and sits at a good temperature according to my temp. gauge, I don't think it's a thermostat issue? If it would be stuck to open position, it wouldn't warm up, if it would be stuck into closed position, it would overheat...what else could it be?

Also, I've checked my radiator hoses and the upper one is hot, while the lower one stays cold, even after a 30 minutes warm up and a little ride around the block. What's this? Coolant isn't going back to the radiator? But engine doesn't overheat...

Can someone help me? I'll check the heater valve cable tonight to make sure it opens fully when the inside temp is set all the way down to hot, but that lower radiator hose (connecting to the engine) that stays cold is really strange.

Thanks in advance...

 

[lethal6]

Sounds like a bad or clogged heater core. You said that in your post but dismissed it in leu of the thermostat debunk.

Also, cold lower hose could be clogged radiator or bad thermostat (stuck open). If it is stuck open, your car shouldn't over heat but with the coolant constantly circulating, the hose would be colder than it should be, as would the coolant it's self.