New? Start here. There are 528 Volvo forum users online now. See the forum's active topics. Say hi contact Matthew.
MVS-Amazon link helps MVS!

How To Diagnose Volvo Heater Problems

volvo heater

Why is my volvo heater not working?

A volvo heater core is a small radiator (matrix) that transfers heat from the engine-cooling system to your car’s air heating/ventilation system. The heater core is much smaller than the engine-cooling radiator in front of the engine. read on to learn more about how to replace a faulty heater core in a Volvo.

First diagnose the problem: is the heater core the prime suspect?

Some symptoms of a heater core leak are:

  • you are losing coolant when the heater is used.
  • you are NOT losing coolant when the heater is NOT used.
  • you can smell antifreeze when the heating is on.
  • you can see condensed vapour exiting vents when the heating is on.
  • your car’s footwell carpet is wet.
  • windows steam up with soapy-looking film.

MVS Forum Member rohosub asks:

Hi, folks.
I’m kind of a newbie here and I don’t know much about cars. I’m an IT consultant. That probably tells you a lot. 😀

I’ve had a Volvo V70 1997 2.0l for 7 years and had no problems with it at all. I’ve never missed a service. It has currently run almost 180.000km.

Recently I noticed that the heater was supplying less heat than normal and this has gradually worsened. I’m from Norway and we have winter at the moment and I tell you. When it’s -15 degrees below zero (celcius) you really need a working heater. At the moment the heater supplies little to no heat at all. The AC seems to work normally supplying cold air and removing humidity. At least that’s what I think. It’s winter…

I’ve checked the coolant. This seems to be at the right percentage and level.

Could someone please give me a hint as to what could be wrong?

I’ve had no problems with the car until now. It is currently using a little bit oil, but not in large quantities. This is probably normal on a 9 year old car during winter, but I’m not sure.

Hope to hear from you guys.

Kind regards


MVS Forum Member White850Turbo replied:

On your instrument panel, where does the temperature needle stay at once the car is warmed up? If it moves at all once the car has been running for at least 10 minutes or it doesn’t get to the “horizontal” position, the most likely problem is that the thermostat has failed. This is an easy item to replace. There is a guide somewhere on this site on how to do it on one of the drop down menus.

How To Diagnose Heater Problems


2005 xc90; heater is on, both climate controls are on the red dot. However, drivers side blows cold air while passenger side blows hot air appropriately. Any ideas?


Heater motor makes noise. How do I replace the heater?

Leave a Reply