How long will it take me to replace my heater core (2000 Civic)?
 

I did not worry about my heater core back in Phoenix, but I am not sure that we have seen 90° here in Show Low yet. It was in the sixties for the Fourth of July fireworks.

Also, what heater core should I use? Honda discontinued it, but someone is selling it on Amazon for $290. AutoZone, O'Reilly's, Napa, RockAuto, and Amazon all have the same Spectra Premium. Amazon has the best price, $62 shipped. Is there any reason I should consider one from a junkyard? There are a couple in Phoenix for $45.

Here are instructions that I found on-line. I promised myself that I would not spend forever writing up the directions for the head gasket and would just get started, but even with supposedly complete instructions, I needed to stop and look up how to do something about twenty times.

1. Disconnect the battery cable from the negative side. Wait a full 5 minutes for the car's PRS Air Bag System to discharge. (The manufacturer's recommendation is to wait 3 minutes; waiting 5 minutes will ensure the system is completely discharged.)
   Disconnect the air conditioner system by disconnecting the suction line and the receiver line from the compressor; unscrew the retainer nuts that hold them in place using a pair of pliers.
2. Drain the coolant from the radiator by opening the drain plug on the bottom of the radiator. Use an approved drain pan to collect the coolant and dispose of it in a method compliant with the laws of your community. Remember this substance is poisonous.
3. Open the cable clamp located under the hood and disconnect the heater control cable. Turn the control valve of the core to the fully open position by hand.
4. Disconnect the heater hoses from the core housing; squeeze open the hose clamps using a pair of vise grips and remove the mounting wing nut from the heater unit by turning it with your hand until it comes free.
5. Remove the center console from the interior of the vehicle using the screwdriver. Remove the gear shift knob and disconnect the heat switch connectors (which should just pull out of the switches); front power accessory port and rear power accessory port (which should just pull out of the socket connectors); and illumination power cables (which should simply un-clamp by hand with squeeze connectors).
6. Remove the lower dashboard panels, driver glove box and center storage pocket using the screwdriver.
7. Carefully remove the airbag assembly from the steering wheel and the passenger side. The airbags are held in place with spring clamps, which will pop open with mild pressure. Be careful to not apply too much pressure--even a discharged airbag may still deploy if too much shock is applied.
8. Separate the steering column assembly from the dashboard unit by moving the column to the fully up position. Use a piece of heavy tape to secure the shaft sliding cover onto the steering column while it is removed.
9. Remove the hoses by opening the spring hose clamps using the vise grips. Remove all remaining wires. Remove the harnesses and retainer bolts using the Phillips screwdriver. Remove the connectors, air bag control computer and center lower covers by squeezing open the hand squeeze clamps. (This may require the assistance of another person.)
10. Lift the dashboard out slowly and remove it from the vehicle by sliding it out of one of the doors.
11. Unplug the connectors from the air mix control motor unit, temp sensor, recirculation control motor, heater ducts, power transistor and blower fan unit.
12. Loosen the heater core cover with the screwdriver and pull the heater core out of the housing unit.
13. Install the new heater core by inserting it into the housing, then securing it in place with the housing cover using the screwdriver.
14. Reconnect and reinstall everything you removed in reverse order.
15. Close the drain valve on the radiator and refill it with fresh coolant. HINT: This would be a great time to perform cooling system maintenance; pick up a flush and fill kit and clean out the engine's cooling system before refilling. You also might want to use a cooling system treatment when you refill, especially if you have an older car.
    
    Test the heating system with normal operation and inspect the whole system for leaks.

https://itstillruns.com/how-to-repla...-12148236.html

Do not get ome from a junk yard. Get a new one, not the $290 one, it's Not worth it.
Just unhook the battery and start working on draining the cooling system at the front of the car.

I never refilled the coolant after replacing the head gasket, so I am one step ahead! :D

After major stuff like that I refill with water only.
It's cheaper if it leaks.

I haven’t taken a look at the heater box in mine. Hondas have a reputation for being easy to work on (which I can largely verify), but something tells me packaging will be an issue. IIRC doing this in a couple classic Mustangs, it was about a four-hour job, but granted, there was hella easy access. I’d at least double it in your Civic.

I definitely would avoid junkyard heater cores - they will probably have worse problems than whatever yours has. Having worked at Autozone, though, I’d be dishonest if I said Spectra made great products. They were fairly high-return items for us, both the radiators and the heater cores.

I wish I knew where to source something better. Maybe the Honda aftermarket scene has something? Or you could pursue it the way I pursued my oxygen sensor, see if an OE supplier still makes it by a different name/part number. My NTK (NTK is NGK’s OE supplier division) oxygen sensor IS, for all intents and purposes, a dealer O2 sensor, since they were the OE supplier for those to begin with. But! for something like 1/3 of the price. Took a couple of days to chase down the OE supplier and part number, but I think it was worth it.

How did you track down the actual manufacturer? Google does not show many results for the part number and everything just says Honda. Napa, AutoZone, and O'Reilly's only show the Spectra core. RockAuto has:

UAC $38.79
OSC $51.99
APDI/PRO $52.79
Spectra Premium $54.99

[plus shipping]

Curiously, when I tried to research Honda heater cores, I found a thread about replacing them in classic Mustangs--nothing said Mustang until I read a bit.

The consensus was that replacing heater cores is easy without air conditioning, but AC makes it terrible.

All I know is that you'd rather talk about it and watch Shouty videos than actually do it, so I voted a few weeks. I'm the same way about things which I think might be frustrating.

This project seems more time-consuming than stressful. I could have damaged my engine replacing the timing belt, head gasket, or some other repairs I have done.

I am mostly concerned with breaking plastic bits, but since you mentioned Shouty, this is how he says to fix that: https://www.youtube.com/watch?v=Hk1cojemglEHow much of that should I order ahead of time? :)

I am unsure where else to look. I have checked Advance Auto Parts, Amazon, AutoZone, Car ID, Car ID eBay, JC Whitney, Napa, O'Reilly's, Parts Geek, RockAuto, Summit Racing, and Walmart. I found heater cores from the following brands:

Spectra Premium
Best price: $45.80 from Car ID on eBay.
UAC $43.82 from Amazon
APDI/Pro $63.78 from RockAuto
OSC $63.78 from RockAuto
GPD $59.38 from Parts Geek
Metrix $79.53 from Parts Geek

It seems that brick and mortar stores offer lifetime warranties while on-line stores discount 50 - 60%, but there is only a one-year warranty.

I never want to do this again, so I am trying to figure out who makes the best one. Still, would I rather have a limited lifetime warranty from Napa for $108 or the same one from Car ID for $45.80?

You're driving a 20 year old car. The last heater core went 20 years, right? Why do you care about the warranty?

It's like when I go to the auto parts store looking for brake pads, and I tell them I want a quote for their cheapest pads. When they quote me, I ask if that's really their cheapest, and then they pull up the PN that is half the cost, but then warn me that it only has a 1 year warranty vs 3. Who cares, it's brake pads. Not only that, but it's the identical brake pads as the ones that cost twice as much.

... and as I always say to people trying to sell me extended warranties, they are either selling me crap, in which case, why are you selling me crap, or they just want free money.

...is it too late for me to change my answer to 6-12 months?