No Heat after changing thermostat and temp sensor.

MrCanada · Post by **MrCanada** » 19 Sep 2010, 09:54

I recently had the car into the shop because the engine light was on. The shop said that the thermostat and temp sensor need to be replaced. I purchased the parts on my own from lordco and attempted to install them myself. Online they said I need to loosen the plastic butterfly nut from the driver side of the radiator. I did not find the plastic release on the driver side but i did find it on the passenger side (live in Canada). I released 2-3 liters, removed the old thermostat and temp sensor and replaced them. I then replaced the coolant in the resevoir at the top of the engine.

I turned on the car and the engine light was still on. I drove it for 40 minutes and noticed that I could not get any heat out of the heaters. What could cause the heaters to stop working? Do I have to worry about the engine light remaining on?

Could one of the parts be faulty? Could the way I refilled the radiator cause air gaps or certain sections to remain empty?

Any ideas would be appreciated.

Thanks.

Post by **billofdurham** » 19 Sep 2010, 11:52

Welcome to Matthew's Volvo Site.

When you replaced the coolant did you do it slowly and was the heater control on max heat? No to either or both and you could have caused an air lock.

When replacing coolant you should occasionally massage the two large hoses that go to the radiator to help rid the system of air. To get rid of a possible air lock now remove the filler cap, set the heater on max, start the engine and carefully massage the two radiator hoses.

The check engine light will stay on until it is switched off using a diagnostic tool or you disconnect the battery. To see what is involved when you disconnect the battery read this.

Bill.

MrCanada · Post by **MrCanada** » 19 Sep 2010, 12:52

I replaced the coolant all at once with the car turned off. I will open the cap and try to massage the hoses.

Should I drain the coolant again if that does not help?

How would I know if the newly installed thermostat or temp sensor was faulty?

Thanks for the advice.

MrCanada · Post by **MrCanada** » 19 Sep 2010, 13:33

Opening the cap and massaging the hoses fixed the heat problem!! Thanks for your help.

I read your link and will try disconnecting the battery. I have the radio code if required.

Please let me know what symptoms to look for in case the new thermostat and temp sensor are not functioning properly.

MrCanada · Post by **MrCanada** » 19 Sep 2010, 15:26

I removed the battery, but the engine light still remains.. I am out of ideas now..

Post by **billofdurham** » 21 Sep 2010, 12:31

If the check engine light does not go out this way then you will have to find someone with a code reader who can erase it for you.

Bill.