# 2013 Sentra heating issues



## datnissan (Feb 2, 2019)

My son has a 2013 Sentra SV that is having issues with the heater. I haven't found any threads with this particular problem (some pre-2008 issues, but not 2013 and above). So here goes...

The car blows air, but it is cold. Well, not cold, but not hot either. Just warmish. It seems to be coming out of all the vents it is supposed to and varies on the amount of air depending on the blower speed control dial. I'm guessing that would tell me the fuses are OK and most likely blower is working as it should. 

I checked the antifreeze level. It was fine.

Then replaced the thermostat. Apparently wasn't the cause.

Flushed the system and replaced antifreeze. Didn't help.

Made sure we burped the system, too. Nope.

Then we back-flushed the heater coil. Nothing gunky came out of it and there was good flow. Topped off radiator and burped. Still no warm air.

I've been reading about a possible faulty heater control valve, but can't find it to save my life. Not sure if it might be inside the water outlet piece that houses the thermostat?

I went inside the car and re-checked the blower motor. It seems to work properly from lowest to highest setting.

Removed the heater/ac control to see if there was a cable that mechanically linked to the heater control valve (the one I can't find). There wasn't one. It is just an electrical plug connection, so a bad cable likely isn't the answer. 

Anybody know of any other components that I may take a look at? Something I've obviously overlooked? The heaters in my old VW were much simpler than this. All I needed to fix those was a coat hanger and a pair of pliers.


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## smj999smj (Jan 1, 2006)

The mode doors are controlled by electric actuators. It's possible that the one for that controls the temperature is not working. If you have auto climate control, there is likely a self-diagnostic procedure that can be run. Refer to the factory service manual for that and for the diagnostic procedures for your symptom, which should be listed on a symptom chard in the FSM. Nico Club's site has free, complete service manuals available.


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## datnissan (Feb 2, 2019)

smj999smj said:


> The mode doors are controlled by electric actuators. It's possible that the one for that controls the temperature is not working. If you have auto climate control, there is likely a self-diagnostic procedure that can be run. Refer to the factory service manual for that and for the diagnostic procedures for your symptom, which should be listed on a symptom chard in the FSM. Nico Club's site has free, complete service manuals available.


Thanks for the help on this. My son just took it to a local mechanic who ran the diagnostics on the car and all was as it should be. However, I did find out there are two thermostats in the car and we replaced that one, too. Double-checked the other one. Put in new antifreeze and bled the system. Still no heat. By the way, I did check out Nico Club's site for the service manual. Can't really find anything that points to anything we haven't done already. You wouldn't happen to have another trick up your sleeve would you?


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## smj999smj (Jan 1, 2006)

I'm pretty sure there is no heater control valve; Nissan started doing away with them around the early-2000's. I haven't worked on any of the later model, Sentras, however, since I left Nissan in 2003. Sometimes air will get trapped in the heater cores on some models, like my R51 Pathfinders. So, try this: make sure the coolant system is topped off in the radiator and to the MAX line in the reservoir and install the caps. Raise the front end of the car as high as you safely can; this can be done by driving the front wheels on a set of ramps, jacking up the front end or parking on a steep uphill with the nose of the vehicle forward. Start the engine and turn the heater "on" to the maximum heat setting. Run the car at approximately 2500-3000 RPM for ten minutes or longer until hot air (about 140 degrees F.) comes out of the heater vents. Shut the car off and lower it down. The next time the engine is completely cold, re-check the coolant level in the radiator and in the reservoir and top off as needed. This works 95% of the time with most, late-model Nissans.


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## datnissan (Feb 2, 2019)

smj999smj said:


> I'm pretty sure there is no heater control valve; Nissan started doing away with them around the early-2000's. I haven't worked on any of the later model, Sentras, however, since I left Nissan in 2003. Sometimes air will get trapped in the heater cores on some models, like my R51 Pathfinders. So, try this: make sure the coolant system is topped off in the radiator and to the MAX line in the reservoir and install the caps. Raise the front end of the car as high as you safely can; this can be done by driving the front wheels on a set of ramps, jacking up the front end or parking on a steep uphill with the nose of the vehicle forward. Start the engine and turn the heater "on" to the maximum heat setting. Run the car at approximately 2500-3000 RPM for ten minutes or longer until hot air (about 140 degrees F.) comes out of the heater vents. Shut the car off and lower it down. The next time the engine is completely cold, re-check the coolant level in the radiator and in the reservoir and top off as needed. This works 95% of the time with most, late-model Nissans.


Thanks. I'll give it a shot. We've tried to bleed the system a few times (including on my sloped driveway), but hadn't filled the reservoir to max and with the radiator cap on. If this doesn't work, do you know if it's possible the blend door actuator could be bad and keeping the door open in the cold position? If so, do you know which one it is? It has three. Two are the same. One is called the actuator-intake air box. That one would be my guess since it... I think... would control all of the vents and not just the floor or dash or one side or the other. We get cold air from every vent.


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## rogoman (Dec 16, 2004)

datnissan said:


> Thanks. I'll give it a shot. We've tried to bleed the system a few times (including on my sloped driveway), but hadn't filled the reservoir to max and with the radiator cap on. If this doesn't work, do you know if it's possible the blend door actuator could be bad and keeping the door open in the cold position? If so, do you know which one it is? It has three. Two are the same. One is called the actuator-intake air box. That one would be my guess since it... I think... would control all of the vents and not just the floor or dash or one side or the other. We get cold air from every vent.


There are two air mix doors which are controlled by door mix motors. They are controlled depending what system you have in the car. If your system is manual, the doors are controlled electrically from the dash panel switch assembly controls. If your system is automatic climate control, the doors are controlled by the A/C auto amp module that's located behind the dash panel switch assembly. There's an intake door that allows either outside air or recirculating inside air but that's not your problem.
Your best bet is to download a copy of the FSM from Nico Club's web site; the section HAC.PDF is the one to read.

If your system is automatic climate control, a portable scanner tool can be used to read out possible DTCs which can help you to diagnose the problem. The DTC codes are listed in the FSM.


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## Carlos2020 (Jan 28, 2021)

datnissan said:


> Thanks for the help on this. My son just took it to a local mechanic who ran the diagnostics on the car and all was as it should be. However, I did find out there are two thermostats in the car and we replaced that one, too. Double-checked the other one. Put in new antifreeze and bled the system. Still no heat. By the way, I did check out Nico Club's site for the service manual. Can't really find anything that points to anything we haven't done already. You wouldn't happen to have another trick up your sleeve would you?



Sorry but I dont know how to use this website and wanted to ask a question because my 2015 nissan altima over heated and now ot wont start. It just makes some whirling sound when I push the push start button. If you know the possible reason or can tell me how I can ask everyone else please tell me. Thanks bud


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