2006 S60 2.5T No Heat At All And It's Freezing outside

faroutman89 · Post by **faroutman89** » 28 Feb 2015, 08:43

I just recently had this problem for over a couple of weeks now. I have a 2006 S60 2.5T with 103K miles on it. Everything runs fine except I have NO heat in my cabin when I crank it high. Just cold air! Here's is what I've noticed:

1) On very cold frigid days (-5 to 15 degrees F) the temp gauge is ALWAYS at the cold mark. Never moves at all even after 30 minutes of driving! I know the needle is suppose to be at the 12 o'clock mark after a few minutes of driving but not mine.

2) On less frigid days (+20 to +35 degrees F) the needle does moves into the 12 o'clock position and I have heat!

I want to take an educated guess and say that it's the thermostat but something tells me that it isn't because if the thermostat is kaput, I shouldn't be able to have any heat at all. But, I do get heat, only at certain outside temperature. Anyone here have this issue before? Any help would be greatly appreciated! Thanks in advance!

Post by **oragex** » 28 Feb 2015, 09:45

The thermostat can be kaput in two ways: either stuck open (the usual fail), or stuck closed. WHen it's struck open, the water pump circulates the coolant continuously through the radiator. This car has a great radiator, which will cause the coolant to never reach hot temperatures. It's very easy to check. Start the engine from cold and let it idle for 2-3 minutes. It will warm up a bit but not enough for a good thermostat to start opening. If at this moment the upper radiator hose is warm to the touch, your thermostat is stuck open and needs replaced. Usually it's the whole housing that's sold, about $100 off Ebay.

The way a stat gets stuck open, is when the small pin inside gets covered with residue and can't slide easily to close back the seal. It can do this more on lower temps than when the weather is more clement.

If the stat checks good, there could be other things to check: coolant temp sensor on the stat housing is busted, the cabin thermometer is faulty, the cabin heater flaps are stuck

faroutman89 · Post by **faroutman89** » 28 Feb 2015, 09:55

Thank you (oragex) for your reply and recommendations! I will do this sometimes today then. As I have been researching since this morning, because I have a turbo, the thermostat is actually an enclosed housing with the thermostat unit built into the metal housing itself. And the ECT (Electronic Coolant Temperature) sensor is also built as part of the housing itself and you are right, it is about $100 on eBay, brand new. Seems like a pretty simple fix, just not today though (-3 degrees outside!) Thanks again!

Post by **oragex** » 28 Feb 2015, 14:33

Here's a not so good video that might help a bit. there is more detail in the video description because I wasn't very good at filming:

Just a little note for the t-stat housing, the one for the turbo model has an extra hose exit, as opposed with the non turbo model, otherwise they look pretty much the same. hope this helps

volvomadness · Post by **volvomadness** » 28 Feb 2015, 16:15

Same car and have the same problem with one additional item. Check engine went on with a coolant sensor believe it was p0116. This caused the fan to come on which further cooled the car. When I clear code the fan stops

When I took the thermostat out it was closed. So I am at a loss.

I would assume that if the thermostat remains closed than the car should heat infact overheat. But in fact the car does not get warm at all. Wonder if it is the coolant sensor can be purchase separately?

Any other thoughts?
Madness

Post by **oragex** » 28 Feb 2015, 17:09

Do you still have the stat in hands? If you throw it in boiling water, you can see if the pin retracts fully when cooled down. It's this pin that usually doesn't fully retract any long, making the stat seal not to close. When disconnecting the rad hose from the t-stat housing, if there is coolant flowing, then the thermostat failed to shut close. The stat usually never fails to open, but rather fails to fully close which causes the not hot cabin air condition.

The coolant temp sensor is screwed right on the stat housing, and I believe it can be removed without removing the whole housing. This would trigger the radiator fan if it (falsely) reads overheating.

volvomadness · Post by **volvomadness** » 28 Feb 2015, 17:41

I did the boiling water now the pin is pretty long and does not seat in the top of thermostat housing after it cooled down.

Any ideas
Madness

faroutman89 · Post by **faroutman89** » 01 Mar 2015, 09:01

oragex wrote:Here's a not so good video that might help a bit. there is more detail in the video description because I wasn't very good at filming

Just a little note for the t-stat housing, the one for the turbo model has an extra hose exit, as opposed with the non turbo model, otherwise they look pretty much the same. hope this helps

I'm curious about one thing, did you drain all of your coolant out or did you just do a partial drain into the bucket? I can only make an educated guess and say just do a partial drain and re-use the coolant again once you are finished with the job. Only makes sense, right? What's your thoughts on that?

Post by **oragex** » 01 Mar 2015, 09:18

I try to catch the coolant as well in a bin and reuse it, as it's quite recent. The first time I did it, I think I only slowly removed the hose from the thermostat and there was some coolant flow (the reservoir cap was closed), perhaps half a liter. The second time I went with unscrewing the bleeder under the radiator, because this way it's less messy, however going by the bleeder will make most of the coolant drain.

faroutman89 · Post by **faroutman89** » 01 Mar 2015, 09:55

oragex wrote:I try to catch the coolant as well in a bin and reuse it, as it's quite recent. The first time I did it, I think I only slowly removed the hose from the thermostat and there was some coolant flow (the reservoir cap was closed), perhaps half a liter. The second time I went with unscrewing the bleeder under the radiator, because this way it's less messy, however going by the bleeder will make most of the coolant drain.

I was a little confused after watching your video towards the end, you said that you replaced only the thermostat. I then realized that your Volvo is a non turbo. But, in your video, you clearly showed that even though it is a non turbo, there is a housing for the thermostat. And you also showed the brand new housing unit towards the end? Can you explained what you did there? Thank you.