Greetings - after the diagnosis mentioned in my Dec 17, 2019 post, I went ahead and swapped out the heater core in the S80 and voila - I now have heat. After unhooking the old core, I turned it over to drain it and a bunch of sediment came out with the coolant, thus confirming there was a blockage i...

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 e...

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 ...

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 sen...

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 leaki...