As the title says, I'm getting barely any heat and with the winter right around the corner, somethings gotta change! Basically what happens is the car will blow "warm" air for a few minutes, then resort back to blowing out lukewarm air even with the heater full blast and the car warmed up. I've changed the thermostat and properly flushed the rad fluid and topped up. What could it be? Vacuum leak? Water pump? Plugged heater core?
I've never experienced this problem on my car, but one place I would check is the heater valve. If that looks OK I would bypass it and see if it gets hot air out of the heater all the time. That would indicate the heater core is not plugged. You might want to trace the hoses back to the engine and see whether there may be obstructions there
Also check that the wire that commands the heater valve is properly attached.
I might say more but I own a 3G so I am even more lost in this case. Hopefully someone experienced will post. My 0.02
Last edited by ecogabriel; 10-11-2009 at 07:22 PM.
If it ain't broke... I fix it!
does anyone know if those have a vaccume control to set which function is working on the hvac system? if they do a bad vaccume actuator or the vaccume canister behind there is leaking and not enough vaccume to operate.Originally Posted by dani_ocean
I'm with Lost, check that your heater doors in the dash are working properly. If the heat door isn't opening all the way, it will make it hard to warm up the cabin.
Dr_Snooz
"I like to take hammers, and just break stuff, just break stuff." - Beavis
1989 Honda Accord LX-i Coupe, 240k miles, MT swap, rear disc swap
Shop manual downloads available here: CLICK TO VIEW
first off, thanks for the help guys. i started by listening in for any vacuum leaks under the dash, but didn't hear anything. the heater doors do open and close fully (theres an audible clunking noise as they slide open) so I don't think the doors are blocked. I did notice a little bit of green fluid (rad fluid?) around the water pump. Could it be the water pump? I noticed somethings been chugging a little more rad fluid then usually lately. The reserve tanks getting suspiciously drained rather quickly but the fluid in the actual rad is still full.
Is this actually a 1g Accord? Or is this in the wrong section? What year is your car? I'm pretty familiar with the 1g Accord if that's what you're actually having problems with, otherwise I need to move this post.
Your heater core prolly plugged. you should have some sort of heat regradless. i dont think the flappers would of mattered of not.
200+ ALL MOTOR LS VTEC
Errm ya, it's definitely an 81 Accord hahaha. Anyways, I'm gonna pick up a Haynes manual and go about removing and flushing the heater core. I'll let you guys know how it goes. Thanks again!
is your carpet wet? its funny that you get some warm air, and then it stops after a short amount of time. that could only mean you're getting hot water for a short amount of time, and then its getting cut off. i cant imagine even a far fetched reason for this scenario... maybe a blockage in the outlet of the heater somewhere, which is choking the flow. it allows higher pressure [is it?] hot water from the block in, until the pressure equalises, and then the flow stagnates...
it seems unlikely
Nah, my carpets are bone dry so nothings leaking. Crazy huh? I ordered a new heater core anyway because I think if the current ones plugged it's probably beyond repair. Anyone ever change a heater core on a 1st gen?
I've changed mine. I pulled the whole dash to do it, but now I wonder if you can't just disconnect the lines and pull it out from the passenger side floor. For some reason I think you have to pull the dash and disassemble the heater control box.
Have you checked the cable to make sure that when you move the slider to "Hot" that it actually opens the valve down there under the dash?
Also another reason you might not be getting heat is if you have an air bubble in the cooling system. When you fill your coolant, you have to make sure the heater core valve is open, or in other words, set the temperature slider to HOT so that coolant can flow into it. And you need to make sure to bleed the air out of the coolant using the bleeder valve located on the thermostat housing. I've made the mistake before of leaving the heater valve on cold while flushing the coolant and not had any heat.
Hmmm...I'm thinking when we changed the coolant we didn't have the heater set. I also noticed this morning that there was a bit of green coolant on a few hoses. Looking quickly, I couldn't find any obvious leaks. Do you think a slight leak could cause a complete lack of heat?
I have a 3rd gen car so can't speak specifically to your model. Assuming you have a coolant recovery tank, what happens if there's a coolant leak is that the coolant in the recovery tank drifts lower over time, until there's nothing left. Then, air is introduced into the system, and I suppose that your heater could have a big bubble in it which could prevent the coolant from filling it up. Here's what you do: Cover the distributor/coil if they're close by. With a cold or somewhat cold engine, fill the recovery bottle to halfway between the low and high levels. Move the heater control valve to "hot." Take off the radiator cap and fill the radiator up. Leave the cap off, and start the engine and let it idle, adding more coolant to the radiator if needed. You will be waiting for the thermostat to open, which you can tell has happened when the coolant in the radiator starts flowing around instead of just sitting there. When that occurs, take a wrench and open the bleeder valve which (at least on 3G's) is by the thermostat. It will start spitting out coolant and air. When it has stopped spitting and just coolant is coming out (don't be in a rush to do this, btw, sometimes a bubble takes awhile to move to the bleeder valve), close the bleed valve, top off the radiator if needed, and put the radiator cap back on (maybe buy a new cap if you haven't for awhile). Flush the driveway with water, as antifreeze is poisonous (very poisonous, and it's sweet) to dogs.
Last edited by w261w261; 10-15-2009 at 10:41 AM.
I'm gonna give that a try tonight. Thanks alot for your help man! I'll let you know how it goes.
That is also my recollection. I had a leaky core on my '76 and the dealer quoted me something like $800 to replace it because there was 8 hours labor to pull the dash to do it.
On the 1g's you'll want to bleed with the engine off.
Dr_Snooz
"I like to take hammers, and just break stuff, just break stuff." - Beavis
1989 Honda Accord LX-i Coupe, 240k miles, MT swap, rear disc swap
Shop manual downloads available here: CLICK TO VIEW
Alright so I drained and filled the coolant last night with the heater on full blast and that seems to have done the trick. However, there's definitely a leak somewhere still. I've noticed a few drops of green fluid splashed a few hoses. This is probably what caused my coolant reserve tank to go dry and let air into the system in the first place. Sherlock Holmes, back to work!
I'd start with a very clean assemblage. Get some Gunk engine cleaner. When everything is clean, then start the engine, let it get hot, and see if you can identify any new spots.
I found the leak (small crack in one of the heater hoses). I replaced the hose and now everything's good to go. Thanks for your help everyone
w00t! Congrats!
Glad to hear of your success. If the heater hose was going, maybe the others aren't far behind. Since they rot from the inside out, and the two radiator hoses get the most stress, you might consider replacing them, or at least inspect one. Remove the hose end from the radiator and take a look at the inside. If it's all dried out and looks suspicious replace it. Far better to do it now, particularly since if it fails on the road you might have a problem getting a new one right away.
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