Small air bubbles inside the radiator cooling system but big impact on idle

A couple of months ago just sending Alza car for water pump replace at the Perodua service center. Since then the radiator temperature tend to increase significantly when the car is on idle for quite long. It could go up to 97 degree Celsius very close to the overheat threshold. However when it gets moving on the road the temperature goes down to normal within the range of 83 ~ 85 degree Celsius. It has been going on like that since then and sometimes need to turn off the engine when parking to avoid the radiator temperature going high.

Thought it could be the water pump - but before going into the trouble of taking it off for inspections I went for the basic maintenance first. So after getting the spill proof funnel from Shopee tried to burp the air bubble which could be the problem. So here is the video of it.

 

After removing the air bubbles from the cooling system - so it was true that those little air present in the cooling system can affect the car coolant temperature significantly. Now the highest temperature on idle is around 85 degree Celsius and rarely go up to 87 which is still within the normal temperature threshold level.

So the lesson learnt from in this case is the present of air bubble inside the radiator (cooling system) have big impact to the coolant temperature. It's best to get them out before any unwanted occur.