b18c4door

93 Civic Sedan, 174K miles, bone stock - got it last week!

So, I have no heat and do live in Iowa, so I need advice - here are the steps taken so far:

1) replaced t-stat and radiator cap with new one
2) mini-flushed radiator with water hose
3) Checked heater valve under hood to confirm working - fluid going to it is HOT and hot after valve as well, so the valve does work. The return hose is warm and not as HOT as the inlet hose
4) Hose holding coolant coming into heater core is HOT, the outlet is warm.
5) Confirmed temp slider in HVAC unit is working and operates the gear below dash which in turns moves valve outside
6) confirmed valve outside is not stuck or wire tension loose by trying to turn valve
7) Can see that the blend door "joint" seems to be working and there is a definite change in temp, cannot see blend door till dash is ripped apart
8) We burped it for about half hour or more like the manual says, we are sure there is no air in it, but interestingly the upper hose has no pressure even after fully warm - can squeeze the sucka easily? Is this normal


So, WTF is left to check...

- Can I have a clogged heater core and is there a way to tell?
- Is the heater core "weaksos"? I have no signs of bad heater core such as leaking fluid, coolant smell etc

Thanks guys and gals. Hope someone has suffered like me and figured out the answer.

b18c4door

wow - anyone!

gsrhatch2356

If I were you I would start with trying to measure temp at inlet and without blowermotor on measure temp at outlet. with no air blowing across the core it shouldnt drop drasticaly but if you see a major diffrence then it probally is clogged. oh or you could just take off the hoses and blow compressed air through it. just a thought. and yea it sucks you cant really verify blend door operation without pulling dash but may make sure that everything else is working properly which it sounds like it is just make sure its not cloged and if its not might as well pull that dash.

MonkeyBoy668

Where did you burp it?

There's usually an valve at one end of the upper radiator hose (on the block in my experience), which is one of the points where air normally gets trapped.

It seems like a lot of people forget about burping from there, which is why I'm mentioning it. And most people who don't burp from there have a soft upper hose. But apologies if you've already done it. I always try to start with the small stuff.

hondamark35

personally i am not a big fan of throwing parts at a problem, but with all you have checked i don't see how it could be much other than a stopped up heater core. try flushind just the core through the heater hoses in reverse or something before trying to get into all that crap under the dash.

even after "burping" or bleeding the air i'll let the car run for a few cycles of the cooling fans, reving it a bit every here and there, with this big funnel on the radiator that holds around two qts. and seals tight with the radiator. i see bubbles come up for a while (with a good head gasket)

b18c4door

OK, address some points:

Burping: We first did the burping by leaving rad cap open. Then I went to FSM and cracked that valve open. I did it by the book. I drive around with antifreeze. Every day after work, I pop the hood open and open rad cap to see if car is released and add antifreeze as needed.

headgasket: I doubt HG could be bad. I checked compression which was at 180 across all four. I checked to see if oil in coolant or reservoir tank. It was clean. So, thats not the issue either.

Flushing heater core: I am yet to do that. Thats my last attempt. I could try to undo hoses and run water thru. I wonder if there will be enough pressure. I almost wonder if those pumps shops use to pressurize the system may be better and push **** out. I just don't trust shops around here to do that. The local honda mechanic is out of town till the 19th, so I may wait till he is back and see what he says. He will just think I don't know what I am doing (like my ex-wife..LOL)

The soft hose makes me perplexed. I burped it out of coolant almost the 1st time as I was desperate to fix it and thought air was in the system!

Thanks for the advice guys/gals. Anything else, please advise!

instrument

do you hear the motor working at all?
or do you turn it on and nothing happens?

b18c4door

oh no, blower fan works and so does the mode motor (defrost vs upper vs upper/lower etc) So, no clogged vents or such issues

HATCHBACK GORILLA!

Ive got the same problem just havent tried yet to fix it....its getting a little colder so it might be time to tackle the problem...... maybe the heater core?

MJobe

Some one help this guy out!

civicx

I have problem with my heat too. When I turn ON the airs coming but its not hot. I move the temperature control to the red but won't go and stuck in the middle. I push and hold its there but when I left go, its come back to middle again. This is the first time, I have problem with heat? Anyone know how I check this and see what's wrong with its. As I read here people are saying HEATER CORE which I don't know exactly where its located and how its looks like. Any help guys/gal....