# Changing heater core



## SentGXE99 (May 8, 2004)

Anyone done this here? My heat does not blow hot unless I am revving or accelerating the motor. I think it may be heater core. I will be buying another Haynes manual since I lost mine. How hard is it and how long does it take roughly? Just need to get an idea on how much time to block off so I can get a baby sitter to watch the kids. I am also probably going to change the radiator hoses as well. Maybe the thermostat too to be safe.


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## IanH (Feb 11, 2003)

try bleeding the system first ??


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## SentGXE99 (May 8, 2004)

I not only bled the system for air bubbles, but flushed it out wih Prestone Super Clean radiator cleaner to get all the crap out, and added fresh coolant, idled it for a while to get the air out and topped off. My mechanic gave it a quick look over and seems to think it's the heater core. Not having any overheat problems. How hard is a heater core swap?


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## Richard Alan (Dec 30, 2008)

SentGXE99 said:


> Anyone done this here? My heat does not blow hot unless I am revving or accelerating the motor. I think it may be heater core. I will be buying another Haynes manual since I lost mine. How hard is it and how long does it take roughly? Just need to get an idea on how much time to block off so I can get a baby sitter to watch the kids. I am also probably going to change the radiator hoses as well. Maybe the thermostat too to be safe.


Sounds like the same poroblem I had with my sentra, try bleeding the air out of the cooling system (there should be a bleeder valve just above the thermostat housing). Do you smell antifreeze (sweet smell)? If not, good chance that the heater core is air locked. Now why are you getting air into your cooling system, in my case it was because of a blown head gasket.


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## Richard Alan (Dec 30, 2008)

SentGXE99 said:


> I not only bled the system for air bubbles, but flushed it out wih Prestone Super Clean radiator cleaner to get all the crap out, and added fresh coolant, idled it for a while to get the air out and topped off. My mechanic gave it a quick look over and seems to think it's the heater core. Not having any overheat problems. How hard is a heater core swap?


I have heard Nissan's had a problem with getting air into the cooling system, what I have heard its because of head gaskets. There are other reason, radiator cap, etc. The key is if you smell antifreeze (sweet smell) in side the car, look under the car back by the firewall for leaks. If you don't smell antifreeze and don't see any leaks, most likely its your head gasket allowing air to get into your system. Good luck.


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## IanH (Feb 11, 2003)

The head gasket problem really started with the 2000 Sentra 1.8, the 1.6 doesnt seem to have the same issue, but i agree it could be a head gasket.
Its also possible the core is blocked, someone adding coolant mixed with tap water could do this.

Remove the glove box, and you will see the heater-fan-A/C unit
See FSM for directions, i haven't done this on this car, download the FSM if you don't have one.
If you cant find a working link i will post one for you.


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## Richard Alan (Dec 30, 2008)

IanH said:


> The head gasket problem really started with the 2000 Sentra 1.8, the 1.6 doesnt seem to have the same issue, but i agree it could be a head gasket.
> Its also possible the core is blocked, someone adding coolant mixed with tap water could do this.
> 
> Remove the glove box, and you will see the heater-fan-A/C unit
> ...


You are correct, there is more problems with the 1.8L head gaskets. How about the spark plug tubes seals that press into the valve cover, (4 each). Do you have any ideas where I can get them, Nissan is telling me that I have to purchase the valve cover. Thanks


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## IanH (Feb 11, 2003)

Not had that problem, but there are threads here. this has been discussed, search and you will find.
I will take a look.....


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## IanH (Feb 11, 2003)

here is a thread, it has aftermarket seals part numbers....

http://www.nissanforums.com/ga16de-1-6l-engine/82869-spark-plug-tube-seals-1-6-a.html


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## SentGXE99 (May 8, 2004)

Yes, I took the sentra out today for a test run. It appears to have a sweet smell when blowing heat. No leaks into the cabin or on the pavement. No oil in the coolant or vice versa. Passed vehicle emmisions today, so SOME good news.


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## jphillips3200 (Aug 28, 2008)

anyone ever try checking the blend door? if a heater core is leaking then it is leaking, you will know it because something will be wet.


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## SentGXE99 (May 8, 2004)

I don't think it's leaking, as far as I can see. I am thinking it may be clogged up, or corroded. I have tried the superflush stuff already, and flushing and bleeding the air out.


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