Heater Core ? for you guys

[PSUArcher]

I am fairly certain that my heater core is due for a replacement. How big of a job is it to replace the heater core? I helped a buddy do it once in an F-150 and it felt like we had to completely disassemble the vehicle to get to it.

 

[theizzardking]

here's a thread on it

http://www.toyota-4runner.org/3rd-gen-t4rs/58352-heater-core.html

here is a link to the fsm so you can have a look at what all is involved,

http://www.ncttora.com/fsm/


i haven't done this, so i can't help you with a write up or anything, sorry, this is just the information that's available to me from the interwebs.

 

[theizzardking]

sorry better thread.

http://www.toyota-4runner.org/3rd-gen-t4rs/45793-help-im-freezing.html

 

[brian2sun]

What is the issue you are having with the heater core? The job sucks to replace one.

 

[PSUArcher]

The last few mornings I have went out early to get my windshield defrosted, and when I come out 10-15 minutes later the defroster is blowing ice cold air. It may kick on for a minute or two while driving, but then goes right back to blowing cold air. It may be possible that I dont need a new core, it may just need flushed. The rear heater is working fine, which makes me think that I need a new core.

 

[topdown4runner]

You might just need a new valve, it is on the fire wall, pass. side near the middle.
Make sure the cable is making it move back & forth ( open & close )

 

[cfranck1]

Ya, I would check to see if that heater control valve it moving. It also sounds like a temp blend door problem. It might not be moving to the hot side. Door actuator might be bad or a disconnected vacuum line??

When truck is hot, carefully grab each coolant line on pass side that go into the firewall. If they are both hot then the Core is not clogged and most likely working fine. If ones hot and the other is not then it's clogged.

 

[brian2sun]

The last few mornings I have went out early to get my windshield defrosted, and when I come out 10-15 minutes later the defroster is blowing ice cold air. It may kick on for a minute or two while driving, but then goes right back to blowing cold air. It may be possible that I dont need a new core, it may just need flushed. The rear heater is working fine, which makes me think that I need a new core.

If you are positive your rear heater stays hot, that's good. Otherwise if all the vents blow cold unless you get on the gas, it could be another issue like a head gasket leak. Before you tear your dash apart, try what the others mentioned before like making sure the hot/cool lever is in fact moving the valve.

If the valve is moving (which I'm guessing it is since you get heat when you're on the gas), the core may be partially clogged and in that case try removing both the inlet and outlet hoses from the firewall and stick a garden hose in the outlet and blow it out backwards with water. If it clears out, put the hose in the inlet and blow it out forwards and repeat in both directions a few times until it blows out nice clean water. I did this to mine maybe a year ago and it's good still. Mine was blowing half heat and making bubbling noises and after flushing it with the hose it blows full heat and is silent now.