Last few days my heating system has been too hot.
I usually set it to 24c for winter driving. I've been driving it for a while and I've been able to control the temperature without problems.

Here's how it feels now.

18c, temperature is cold
19c it feels like 26c
20c, it feels like 32c
Anything over 20c will feel the same 32c.

What's happening and how can I fix it?

 

Set a thermometer near the cabin ambient sensor (driver side below the steering column, looks like little vent slits cut into the trim plastic) and get an actual reading of ambient temperature. Not the air blowing out of the vent but rather cabin ambient temperature. The temperature you set is the target ambient temperature the system will try to hit, if the temperature probes have cold air blowing on them from a window being open or something else it will turn the heat up to correct.

Do you have anything on the dash that's covering up the sunload sensor (round plastic looking thingy at the edge of the dash near the edge of the defroster vent openings by the windshield).

Did you accidentally put the system in dual mode with one side turned really high?

 

If none of those items work then check the FSM under section ATC.

http://www.nicoclub.com/archives/inf...e-manuals.html

 

It might be too cold outside.
It seems to be back to normal now after I turn it up to 32c for few minutes, turn it to 18 for a few minutes and then I use AUTO (A/C on). Maybe this reset the temperature sensor or computer?

It's all good now.

 

I know from experience that having the system set to a target like 90 F which is the max temp with the WINDOWS DOWN during the winter (yeah I like the sunroof open and windows down when it's freezing with the seat heaters on high and the system heat turned to max) that it blows some INSANELY hot air out of the vents, almost hot enough to burn your skin if you hold your hand in front of it.

System will try it's hardest to hit that target temp you set. If you have a little draft that's moving cold air into the ambient sensor then it's going to think it's a lot colder in the cabin then it really is and compensate accordingly.

 

So dumb question of the day, but my heat isn't very hot and I don't have air in the system. Does this mean I need to back flush the heater core to clear it up and get more heat?

 

Maybe, but it would only make a difference if you suspected there was crud in it, I would FULLY disconnect the heater core and adapt over to a garden hose to backflush though, you really don't want loose sediment breaking free of the heater core only to jam up in the radiator...

Stick a thermometer in the vent with the temp on high and see how hot it really is.

 

Ok Urban I took this pic today, system on high (you can see settings in the pic) but with RECIRCULATED AIR, it was a little above freezing outside (34F I think)and it was blowing 140F (60C) air out of the vent. I could see every time the thermostat opened because it would spike to 150F then trickle quickly back down to 140F.

Wasn't kidding about it being hot enough to burn your hand, hope this helps for reference.

 

Sheittt yours is way hotter than mine. I'll have to plan for a flush in the spring !

Thanks as always .

 

Also keep in mind that I had the windows down, sunroof open so it was cold inside the cabin, the system throttles back considerably when inside temps reach about 60 F cabin temps even though the target temp was still at 90 F.

If you're running the nismo thermostat (or others that open at 155 F instead of the stock 170 F) then it will translate to cooler air for the AC, I believe the same would apply to a higher efficiency radiator but don't quote me on that part, I can't remember exactly where the heater core supply is drawn from.

 

Quote:

Originally Posted by cleric670@gmail

Also keep in mind that I had the windows down, sunroof open so it was cold inside the cabin, the system throttles back considerably when inside temps reach about 60 F cabin temps even though the target temp was still at 90 F.

dude I've read a lot of your posts and you have a serious wealth of knowledge as pertains to the G's... cleric670@gmail
so unfortunately for you I've decided that it I'm relocating to WA and you're gonna be my new best friend... lolz

j/k

 

Hah! Just stay over on the west side of the cascade mountains and you can drive your G year-round. Over on my side of the state we have to park our fun cars for the winter and drive the 4WD.