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05 Accord Ex heater core is leaking (I think)


Pawl
09-24-2011, 02:41 PM
118,000mi update - Everything is Honda Genuine parts - I just changed radiator and radiator cap, thermostat, water pump, upper/lower radiator hoses,all heater hoses,coolant,serpentine belt,belt tensioner. I am a preventative type person. I travel alone around the USA and I would rather change this stuff at home and not have to worry. I had no problems with car before I did all theses changes.
Is the heater core possibly the weak link in all of this and has a small leak. I saw where the blue coolant was leaking on the carpet on the passenger side down by where your feet would rest or basically under the heater core. I also found the overflow reservor low so I topped it off and have not drove more than 25 miles and reservoir is low again and more blue coolant is on the carpet. I have been a typical backyard mechanic for the last 45 yrs. I thought I read something in the Haynes manual that made me think I might have to deal with the A/C when I go to replace this heater core. And would everyone agree that it sounds like the heater core? Thanks Guys. Any thoughts?

jgr7
09-24-2011, 06:17 PM
118,000mi update - Everything is Honda Genuine parts - I just changed radiator and radiator cap, thermostat, water pump, upper/lower radiator hoses,all heater hoses,coolant,serpentine belt,belt tensioner. I am a preventative type person. I travel alone around the USA and I would rather change this stuff at home and not have to worry. I had no problems with car before I did all theses changes.
Is the heater core possibly the weak link in all of this and has a small leak. I saw where the blue coolant was leaking on the carpet on the passenger side down by where your feet would rest or basically under the heater core. I also found the overflow reservor low so I topped it off and have not drove more than 25 miles and reservoir is low again and more blue coolant is on the carpet. I have been a typical backyard mechanic for the last 45 yrs. I thought I read something in the Haynes manual that made me think I might have to deal with the A/C when I go to replace this heater core. And would everyone agree that it sounds like the heater core? Thanks Guys. Any thoughts?

Are you sure your heater hoses that you changed aren't leaking? Did you have a neglected cooling system before you did all this work? I can't see how changing all the other stuff would lead to the heater core leaking unless you damaged it while changing the heater hoses or one is leaking. If your cooling system was severely neglected the heater core could have some rot that would lead to a leak but your mileage is pretty low for it to just start leaking.
Jeff

Pawl
09-24-2011, 11:25 PM
When I put all the new parts on and drove the car I noticed my coolant reservoir was down a little bit after filling it. I found the lower heater hose by the firewall heater core connection wet with coolant on the bottom side. I had just reused all the old spring clamps(or whatever they call them) and thought maybe this one wasn't getting the job done so I installed one of the old type clamps that require a slotted screwdriver to tighten it.After filling the reservoir and driving the car the outside of the heater hose was no longer wet.
The very first and only time I cleaned up the beige carpet inside I thought I had removed all of the blue coolant off the carpet. When I opened the hood today with the motor cold I noticed the coolant reservoir was halfway between Max/Min. I thought maybe the heater core was leaking because I opened the passenger door and I could see some blue color in the carpet.
I had to drive the car today so I took off and when I came home I opened the hood and the coolant reservoir was just a shade above halfway between Max/Min. I opened the passenger door and touched the carpet and realized it was dry. Earlier today I did not touch the carpet. I assumed it was wet because I could see shades of blue carpet.I think I had been fooled by the little bit of blue coolant that was still there from the first time I cleaned the carpet,plus it was daylight and my carpet is beige.
I have put about 1000 miles on this car since I first changed everything. I use the AC about 80% of the time and the heater about 20%. I was traveling last year back east and using the heater quite a bit with no problems.
That heater hose I found that was wet on the bottom is pointed toward the firewall when I attached it and I am wondering if under pressure some coolant was just getting into the inside of the car and just running down the carpet versus the heater core actually having a leak in it.
Lastly is it possible there could be any air pockets left in the system and once they work there way out the coolant in the reservoir is being drawn into the system lowering the coolant levels in the reservoir.

jgr7
09-24-2011, 11:33 PM
When I put all the new parts on and drove the car I noticed my coolant reservoir was down a little bit after filling it. I found the lower heater hose by the firewall heater core connection wet with coolant on the bottom side. I had just reused all the old spring clamps(or whatever they call them) and thought maybe this one wasn't getting the job done so I installed one of the old type clamps that require a slotted screwdriver to tighten it.After filling the reservoir and driving the car the outside of the heater hose was no longer wet.
The very first and only time I cleaned up the beige carpet inside I thought I had removed all of the blue coolant off the carpet. When I opened the hood today with the motor cold I noticed the coolant reservoir was halfway between Max/Min. I thought maybe the heater core was leaking because I opened the passenger door and I could see some blue color in the carpet.
I had to drive the car today so I took off and when I came home I opened the hood and the coolant reservoir was just a shade above halfway between Max/Min. I opened the passenger door and touched the carpet and realized it was dry. Earlier today I did not touch the carpet. I assumed it was wet because I could see shades of blue carpet.I think I had been fooled by the little bit of blue coolant that was still there from the first time I cleaned the carpet,plus it was daylight and my carpet is beige.
I have put about 1000 miles on this car since I first changed everything. I use the AC about 80% of the time and the heater about 20%. I was traveling last year back east and using the heater quite a bit with no problems.
That heater hose I found that was wet on the bottom is pointed toward the firewall when I attached it and I am wondering if under pressure some coolant was just getting into the inside of the car and just running down the carpet versus the heater core actually having a leak in it.
Lastly is it possible there could be any air pockets left in the system and once they work there way out the coolant in the reservoir is being drawn into the system lowering the coolant levels in the reservoir.

I have never had any air pockets but have read about all kinds of people having them, Many times it will cause it to over heat. Do a search about purging or bleeding the air out of cooling system and you will most likely find the answer and how to bleed the air out.
Jeff

Pawl
09-25-2011, 01:04 AM
I looked through my Haynes Manual and there is no mention of purging or bleeding but I remember when I first added the new coolant I just let it keep running with the cap off and the air bubbles kept working their way out through the top as the motor warmed up and the thermostat opened.I might just try doing that again.I might be almost there to where all the air is finally out and just don't realize it.
I don't see any coolant on the ground and it has never run hot on me and I have owned it since 2008 and this car was like brand new when I bought it. I have never even smelled any coolant inside the car. And I know that smell from being in other cars that had coolant problemsThe motor doesn't burn any oil. Thanks for your help on this. I will post what I find out in a couple of weeks.

somick
09-26-2011, 12:25 PM
Both my son's 95 and mine 99 Accord have bleeder screw on the thermostat housing.

For test purposes you can by pass your heart core and see if your antifreeze level will stop dropping.

Good luck,
Sam

Pawl
10-09-2011, 09:44 AM
10-9-11 update. I might have just needed to wait a little longer to get all the air out of the system because in the last couple of weeks the reservoir is almost at the same level everyday now. I think in the morning with the motor cold and weather a little cooler it is about a 1/2" down between maximum and minimum on the overflow container.Once it warms up I open the hood after driving and then the coolant level will show it at maximum. So far so good. Thanks for all your help on this.

Pawl
10-23-2011, 06:33 PM
Oct 21st - I went for a 30 mile ride Friday night and used the heater on the way home. I got up Sat morning and checked the carpet inside on the passenger side. I had pulled the carpet back where the coolant was staining and placed a clean white rag in its place. The rag had blue coolant stains. Today is Sunday so I took the small heater hose off the heater core connection and noticed the male connection for the heater core,the one I have been dealing with was slightly oval. I think I might have tightened the old style hose clamp too much when I put it on. I looked at the nu heater hose I took off and it looked fine.I am wondering if the connection being slightly oval with a round heater hose was enough of a problem to allow it to leak.I am not talking about a lot of fluid leaking. I am talking about when I open the engine compartment and check the overflow reservoir it is down a 1/4 of an inch each time so it will add up to become an irritating problem. But the problem only occurs with the heater core circulating coolant so in the winter it will continue as I use the heater more. The small hose where I think it is leaking where it connects to the male connection on the heater core is on the side just below the valve that opens and lets the coolant circulate so if I don't use the heater there is no leaking. I actually think if the heater core was leaking I would have more fluid leaking out then what I am seeing.
With that said I am thinking about putting some blue silicone inside the heater hose at the one end that connects to the core connection. I am not going to take this hose off again for another 120,000 miles. I can gentley squeeze the oval connection back to round,put the old spring clamp on and see what happens. I grabbed on to the heater core connection and it is so rigid I am thinking there is no way I could have damaged it. It is solid. I just can't believe the heater core is leaking when it was fine before I changed everything.
Plus it looks like a big job to change a heater core. I want to try everything first to fix this leak before I do that.

Pawl
10-25-2011, 08:06 PM
Oct 25 update - I put blue silicone on the inside of the end of the short piece of heater hose that connects to the heater core. I put the original spring clamp on the hose and let it dry for 24 hrs. I filled the system and started it. The hose started dripping more than it did before. I drained the system again and put the old style hose clamp back on that tightens with a slotted screw driver and snugged it versus overtightening. I filled the system and started the motor and so far no leaks. The overflow reservoir is still on max and nothing has leaked inside of the car where it did before. Go figure! I might have figured out what was causing it too leak inside the car early on but I had to figure out where it was coming from and I might have got lucky. Hopefully I can move on to some other problem. They just keep coming. They call it life.

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