Heating issue - Cold air from driver vents

[RollaDriver]

Hi,

My 05 Avensis started running hot (higher than normal temp, over heat) and blowing cold air from the vents. I checked the coolant and it was a bit on the low side.  After topping the coolant up it was having the same issue of blowing cold air from the vents.  After some trials I have noticed  that if I don't turn the fan on until the engine is warm (normal temp) the engine won't overheat but will only blow warm air from passenger side vents and cold from the driver side.  I have had the thermostat replaced with bleeding/burping the coolant system which has had made no difference.   The air is still cold on the driver side.  Has anyone come across this before?

 

Thanks

 

[Michael88]

Having a similar issue. Had to keep topping up the coolant. I only would get heat occasionally but full heat when driving on the motorway. Brought to a mechanic couldn't find anything wrong, tried another mechanic he found a tiny leak in the rad. Changed the rad and car coolant now at the right temp and car not over heating. However heater still the same. Blend door actuator working perfect. He also bled the system and no airlocks. I wonder is my thermostat not working correctly now. 

[Billyboy81]

Try changing the cabin/pollen filter. Only a few pounds and will prevent airflow if blocked. Worth eliminating before embarking on expensive repairs. 🙂

[RollaDriver]

I have taken the pollen filter out and it made no difference.  So i cleaned the current one which has small pieces of leaves in it and put it back in.  Still no difference.  scratching my head.... 

[Robert81]

That is strange...I would normally think that there is air in the heater matrix but you both had the system burped.

Do you know if the temp setting was on the highest when burping the system???

[RollaDriver]

I took the radiator off yesterday and flushed it,  refitted it.

The temp was set to high and the direction of flow was facing the front so blowing towards the driver & passenger.  Initially it was cold air coming from the vents. then after 10 mins or so it got hot.  I've checked the two pipes coming going towards the firewall (heater matrix) and they are hot.

The top fat pipe on the radiator is hot, bottom pipe is cold even after running half an hour and the fan didn't kick in.  I replaced the expansion tank pressure relief cap with  a new one and  took it for a spin.  Drove it for 15 miles with the radiator on HI,  Passenger side vents were toasty, driver side are still cold. When I got home the temp needle went just above the half way temp then came back down just below half way.  Lifted the bonnet and both fans were on for 20 seconds then turned off.  The radiator side where the top pipe feeds into was hot but the bottom pipe and radiator side were cold.  I didn't dare touch the radiator in the middle between the fans just in case the fan started to spin.   

 

[RollaDriver]

I also took the top sensor out of the radiator to see if there was any air inside the rad but coolant flowed as soon as I unscrewed the sensor.

[Robert81]

Hi, did you squeeze the hoses to ensure no air is trapped? and rev and hold the engine up to around 3000RPM for few seconds (let idle for a minute after that) - this needs to be repeated couple of times. Also make sure you wear gloves as they will be hot and stay away from the fan just in case it kicks in.
As before, the temperature needs to be set on HI and speed on low so it can heat up nicely to let the thermostat open itself and heat up allowing for the FANs to kick in.

 

If you are sure that no air is left / trapped in the system, i think you might have a blocked heater matrix or an issue with the damper. Those would be my bets based on my re-search.
Unfortunately, I do not own a T25 but your interesting case made my look for possible cause of your problems. Some people flush the heater matrix and it fixes it or just replace it with a good second hand unit.

[Robert81]

PS. I can't guarantee this is your problem but definitely worth looking into this. 

[Exvec]

 I had this problem on mine. What i did was reverse flush the heater matrix,there's  a How Too  video on uchube shows you what to do it.Also if you can leave the car with the radiator cap off with the nose facing uphill over night,this should get rid of any excess air in the system,well it worked on mine anyway.

[SeniorH]

I also have this problem, of course I only noticed it now because I have been riding my bike to work so far.
Toyota avensis 2.2 d, 2009, in the spring my mechanic changed the new air conditioning, and I have only used the air conditioning so far because there was no need for heating.
A few days ago it got cold and I noticed that my heating works less, but on the driver's side it works but not at full power, when it blows on the glass it also heats but not at full power.
It blows cold in the passenger seat, and it blows cold in the cabin opening when the heating is at its strongest.
i have enough fluid in the system, and following the advice written above, i opened the radiator cap and will leave it open overnight, maybe air will come out of the system if there is any. The car is flat, and I will try to find a slope tomorrow so that the radiator cap is elevated.

I'll report the result tomorrow, because it's minus 3 in the morning, and I don't want to drive a car with gloves.

[SeniorH]

I have to admit that this is the most perfect solution for venting the system so far. At eight o'clock in the morning I re-parked the car so that the cap on the radiator on my elevated, topped up a crumb of water and left the radiator open. I didn't have the nerve to wait so after an hour I went to see if there were any changes, and the water level dropped. Now after 3 hours I went again to see if there were any changes and the water level dropped again. I didn’t start the car, I didn’t move it and the laws of physics made their own. Perfect. I still have six hours until dark, and finally tomorrow I guess I have full heating in the car.