2007 S80 heater not working

Wetlander · Post by **Wetlander** » 28 Oct 2019, 18:35

I'm driving a 2007 S80, newer generation with 128K miles. I'm not getting any heat from drivers side vents, and only a very, very slight amount of heat from passenger side vents. Same for windshield defroster. Blower fan seems to work fine and AC works very well. Have not witnessed any coolant leaking onto floor and no coolant smell in cabin when asking for heat and blower is on. Wondering if I should be looking at thermostat, heater core, damper motors, or something else? This is a new car for me, and it's my first Volvo, but I'm interested in trying to figure things out, so any help is much appreciated. Cheers!

Lembit · Post by **Lembit** » 13 Nov 2019, 10:29

Hi
First suggest is to chek coolant temp with diagnostics appliance, if coolan temp is low ( less than 80 degrees) after you have drive at least 20 minutes, probably is problem with thermostad. Also wight be problem temp sensor which controll fans. Does fan working all the time?

Lembit · Post by **Lembit** » 13 Nov 2019, 10:53

Ther might be several problems.
* Chek coolan temp with diagnostik appliance, if this low even you been driven dard. its probably problem with thermostat.
* Maybe coolant sensor is dead, it causes fan working while they shouldn t work
* Maybe fan controll modul is dead,
* Maybe cabin filter is dirty

Wetlander · Post by **Wetlander** » 16 Dec 2019, 00:44

Hi Lembit- Thanks for the reply. I replaced the thermostat and flushed the coolant today. While the thermostat I removed was broken (part of the plastic housing was broken and the spring was lying loose), I still do not have any heat after the new thermostat was installed. Will look into coolant sensor and fan control module next. Cabin filter was replaced not long ago, so I don't suspect that is the problem, but I'll check that as well.
Cheers!
Eric

Lembit · Post by **Lembit** » 16 Dec 2019, 03:41

Hi
I think you replaced wrong parts.
Thermostad is made by aluminium and locate behind egr and trhottle body.

Post by **jimmy57** » 16 Dec 2019, 12:59

On a 3.2 liter 6 cylinder the thermostat is on the block and is a black plastic housing with a thermostat integrated. Try turning the temp knobs to full cold, the lowest temp it will go to. Wait 2 minutes and then set knobs to highest temp and wait a minute or so. The full range temp settings forces a calibration so that might get it hot again. There is no hot water valve on that car to cause a problem but you could have a partially plugged heater core not allowing much hot water flow. When heater core gets blocked the little heat you get will vary left and right

Wetlander · Post by **Wetlander** » 16 Dec 2019, 13:13

Thanks, Jimmy. Your description of the thermostat matches what I replaced. I will try out your suggestion for fiddling with the temperature settings later today and let you know if that helps.
A friend also suggested that there might be a door or damper that allows or restricts air from being blown over the heater core, and if that door is somehow restricted from opening, then the air won't flow over the heater core and therefore won't get warm. Would this also be a possibility for what might be wrong?

Lembit · Post by **Lembit** » 17 Dec 2019, 06:21

I told it for 5 cylinder 2.4 liter engine

Wetlander · Post by **Wetlander** » 17 Dec 2019, 07:06

So I tried Jimmy’s suggestion of running the temp low then high, but it didn’t make any difference. Next, I visited a friend, who is a mechanic, and he helped me determine that it appears to be a problem with the heater core. We exposed the coolant lines running into the core, and while we ran the engine only the in line was hot while the out was cold, suggesting a blockage in the core. We tried “burping it” by revving the engine multiple times to try and dislodge any potential air bubbles or other particles, and while this temporarily would cause the out line to heat up and resulted in a bit of heat from the passenger vents, it quickly cooled back down once we stopped the revving. Anyway, thinking it’s time to replace the heater core. Anyone know of any tutorials for doing so on a third generation S80?

thelwthelw · Post by **thelwthelw** » 09 Jan 2020, 11:16

Hi there, I also have an issue with the heat. It is not working... I checked the blower fan and it is working. Next I checked the heater core and both in and out lines got hot... I believe there is an issue with a dumper motor or the heater resistor. I am waiting for a diagnostic tool so I can check before taking the dashboard apart. Did you finally figure it out? what was the issue?