Coolant Pressure/low Light

[salam0506]

Hi Guys,

2006 A3 TDi - BKD with 90,000mi

Read quite a few of the coolant posts on here but I am not entirely sure might is losing any coolant... basically driving on the motorway about a week ago the light came on so I stopped off and saw that the level was just slightly below minimum. Then again the light came on this week and then again today and it flashed longer than last time. Checked level as soon as I stopped and it was lower this time below the minimum but as soon as i released the pressure when taking the cap off the reservoir the level returned to minimum. I am not entirely sure how the pressure works in the system. Does anyone have a clue as to what I should be looking for?

Cheers
Seenan

 

[NHN]

Needs pressure testing to see if its an external or internal leak.

 

[salam0506]

sounds like a dealer job? or can someone else do it for a bit cheaper?

 

[NHN]

Any good technician will have the tools to do this.

 

[salam0506]

Is it right to assume that it is most likely an air leak as the water level seemed to return back to the minimum level when the pressure was released from the filler cap?

 

[Geraldy212]

If the system had pressurized there is probably no air leak. The cooling system is a 'closed system', in that it is all sealed off from the atmosphere. As noted above, it is a good idea to have the cooling system pressure tested. It is not a good idea to take off the filler cap until the engine has cooled down. What could be happening to you is a bubble of air trapped in the system. That could account for the sudden coolant level changes. Inside the coolant tank there are two metal prongs which detect the coolant level. These sometimes need cleaning (scraping with a screwdriver) in order to work properly. Good luck.