Heater Issues

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I have no heat in my S14. Been working on this periodically when I come back from school here and there and nothing is getting accomplished. Any feedback would is appreciated.

-Blower motors come on, it just only blows cold air.
-When I go from hot/cold I see the bypass valve in the engine bay open.
-When I go from hot/cold I see mechanics moving under the dash.
-Drained coolant, back-flushed my whole system out with a hose through to top heater hose on the firewall.
-New thermostat put in correctly. Even boiled it to make sure it opened.
-Tried burping the system multiple times. Each time it just spurts boiling coolant out of the radiator.
-No coolant leaking from the heater core.
-Top heater hose on the firewall is hot, bottom is cold, and I know water flows in and out of the heater core, tested in by hand.

I'm sure I've done more I'm forgetting. I'll try something new each time I come back into town. That's the majority of things.

Do I just bite the bullet and try swapping in a new heater core, even though mine isn't leaking?

I just want heat, damnit.

[gabes240]

How dirty was the coolant when u drained it? If the coolant is very old and cruddy suffers from electrolysis it can clog the heater core which sounds like the problem. I have swapped heater hoses in the past and have seen good results, not 100% might be worth a try though just to make sure.

[Beemer]

you can flush the heater core its pretty simple.

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you can flush the heater core its pretty simple.

I've already back flushed the heater core too, no luck with that.

[Hoffman5982]

I'm actually having the same issue.

[Raptor Jesus]

Same here except mine gets lukewarm after about 30 minutes. but not HOT. so annoying.

[Raptor Jesus]

Same here except mine gets lukewarm after about 30 minutes. but not HOT. so annoying.

Is there a checklist to diagnose? my coolant was fine.. should i just go ahead and replace the thermostat

[rcdad123]

im not sure about s14, but my s13 has a separate valve in one of the plastic pipes on the heater core itself. this is hooked up to an arm that is hooked up to a solenoid that moves the arm to let water flow thru the heater core.

[EDacIouSX]

yea.... i have the exact same problem. my heater gets luke warm on cold days... FREAKEN annoying. My heater core was clogged like a mofo and I cleaned it out by running a hose through it for about 20 minutes.

I don't know if it's my thermostat (not sure if I have one) but I am wondering if there could be something more to it than that?? I'm going to watch this thread and see what other input people have!

[Agamemnon]

I have no heat in my S14. Been working on this periodically when I come back from school here and there and nothing is getting accomplished. Any feedback would is appreciated.

-Blower motors come on, it just only blows cold air.
-When I go from hot/cold I see the bypass valve in the engine bay open.
-When I go from hot/cold I see mechanics moving under the dash.
-Drained coolant, back-flushed my whole system out with a hose through to top heater hose on the firewall.
-New thermostat put in correctly. Even boiled it to make sure it opened.
-Tried burping the system multiple times. Each time it just spurts boiling coolant out of the radiator.
-No coolant leaking from the heater core.
-Top heater hose on the firewall is hot, bottom is cold, and I know water flows in and out of the heater core, tested in by hand.

I'm sure I've done more I'm forgetting. I'll try something new each time I come back into town. That's the majority of things.

Do I just bite the bullet and try swapping in a new heater core, even though mine isn't leaking?

I just want heat, damnit.

According to the FSM, you have done everything to diagnose the issue except replace the heater core. You might as well give it a shot.

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According to the FSM, you have done everything to diagnose the issue except replace the heater core. You might as well give it a shot.

That's what I thought too, just didn't want to go about pulling my dash considering it's never been out of this car yet.

yea.... i have the exact same problem. my heater gets luke warm on cold days... FREAKEN annoying. My heater core was clogged like a mofo and I cleaned it out by running a hose through it for about 20 minutes.

I don't know if it's my thermostat (not sure if I have one) but I am wondering if there could be something more to it than that?? I'm going to watch this thread and see what other input people have!

In the FSM there is a page dedicated to going through and testing each thing. I'll see if I can find it for you.


I'll be home this weekend, so I'll see if I can flush the core itself out again.

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http://farm9.staticflickr.com/8241/8495994785_93d6dc0ea4_z.jpg

[240sxdriftin]

set it on fire

[Nismo-kouki]

My heat blows hot out of the vents but when you blend it (vents and floor) its luke warm coming from vents and hot on the floor.

My kouki has never had really hot heat like my other cars. It has been meticulously taken care of all services have been done its entire life. bought it from the original owner who was a 60yr old man even the brake fluid was clean.

[omgosh]

I have a KA that would NOT bleed all the way. I had to drill a couple small holes in the thermostat to actually get all the air out. The heater will not be very hot if there is still air in the system, as it likes to get trapped in the core. You can try taking the thermostat out and see if there is heat (once it finally warms up).