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Hi all,

Been searching, but haven't found a write up for how to replace the heater core.

I believe mine is blocked, and it might be leaking as I was getting a coolant smell in the cabin. As a part of my cooling system overhaul, I've decided to get it out and take a closer look.

Any pointers / instructions on how to get to it and get it out?

Thanks in advance!

 
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I'd want to make damn sure it's a problem, as it's gonna require pulling the dash out along with discharging the freon from the AC.

If you think it's clogged, flush back and forth with the garden hose. Make sure the water valve is wide open first.

If you had other cooling system issues you may have been smelling them instead of the heater core. I have not witnessed one leaking as of yet in my little corner of the planet.

 
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Thanks Ez. The AC is discharged at this point, so I have that going for me. I bent the crap out of one of the tubes going into the heater core in the engine bay just outside the firewall. Have to figure out how to get it back to round. I have had all kinds of cooling issues for sure.

On the valve, how do you make sure it is open? I have the battery out and just about everything out of the engine bay that can come out. Can I mechanically open it? Which way is open?

 
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If the HVAC panel temperature was set on full cold when the ignition was last powered up I'd assume the valve should be in the closed position to block flow through the heater core..

Conversely, if the temp was set to full heat I'd expect the valve to be wide open for water flow through the heater core.


If the valve is closed----disconnect the cable, move the lever by hand? It swings about 90* from open to closed.

HTH

 
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Awesome, that is what I was thinking to do.

Good news. I fixed the bent inlet pipe to the heater core, attached some plastic tubing to it and to my garden hose and plastic tubing to the other hose out to a bucket. Turned on the water, and out flowed a bit of coolant, followed by water. Seemed to be flowing through as fast as it was going in with no back pressure. So I guess that means my heater core is not blocked. Which means no need to take the dash out, Yeah!

Bad news, I have no idea why my car's engine temperature gauge would sky rocket previously whenever I turned on the heater. Perhaps the heater valve itself is broken?

Going to take your advice tomorrow and see if I can get the valve to work manually when I take off the cable.

Any other thoughts as to why the heat would spike on the temperature gauge on the dash when I turned on the heater? It happened consistently, and directly after turning on the heater, about 30 seconds after, the temperature would start to rise. Perhaps a block some where else?

Thanks!

 
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No real ideas here. The heater core is the same as an extra radiator and increases cooling capacity when in use, so I might suspect an electrical issue causing your gauge to give a false reading....and maybe carry out a few other checks to verify if what I saw is true or false.

???

 
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Hmm. Ok.

Getting nearer to putting this whole mess back together. I want to check out every part of the cooling system along the way.

My list to inspect:
- radiator, thinking to fill it under pressure and see if it leaks
- hoses, going to replace them all I think. Not sure how much that will set me back or what to order, but I'll figure it out I guess
- thermostat. Just replaced it
- fan switch, ECT switch
- fans and fan motors
- water pipe behind block (does this come off easily) couldn't get it off yet.
- water pump, replacing as a part of timing belt
- heater control valve.

Anything else?

 
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Stop.
Beg borrow or steal a real cooling system pressure tester.

Normal household water pressure is far higher than what a cars cooling system is designed to withstand.

Are you in Canada or the rust belt? I'm in the rust belt and I haven't seen any rust out here but I hear they do farther north of me.

I THINK after you get one end exposed it's got 2 bolts on the back of the block and one tough O ring holding it into the back of the water pump.

 
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Not in the rust belt. No visible rust on it.

I will see if the local store has a radiator pressure kit I can rent.

Thanks!

 
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Still trying to figure out how to get that water pipe off.

I got a new head gasket kit, and I think it may have come with a flange for the water pipe / pump.

Here are the pics of the back side and the water pump side of the pipe. Just can't figure out where it is stuck.

 
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I think it should be an O ring, and you don't HAVE to try to use all the seals and whatnot in a gasket set if you don't really need them to get the job done.



Did you get the bolts out, is the pipe now loose enough to wiggle??

If you are down to having it stuck in the back of the water pump, spray something (silicone?) in between the pipe and casting to get the O ring wet and lubed. Use the welded peg on top of the pipe, place a screwdriver (or something to act as a wedge) between it and the casting and gently pull the pipe upward, then move the screwdriver and repeat to work it outward slowly while wiggling.

 
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Awesome Ezone, will do. Yes it is loose and I can wiggle it. Haven't tried applying any force yet.

Please check my thread on valve job, important message for you there

 
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http://www.mediafire.com/file/oawmyl...em2_repair.zip


Civic repair and maintenance > see diagram on page 20-225

 
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got myself a digital manual know also)