My driver side heater is blowing out cold air. When engine is switched off I have noticed a gargling and swishing sound behind the center console almost like bubbling. Have taken a flash light and examined the engine area no visible signs of leakages ? Any more clues guys Thanks
The gargling / swishing noise sounds like you might have an air lock in the cooling system, which could account for poor heat output if an air lock is preventing the coolant from circulating effectively around the cooling system and into the heater matrix. Some new cars leave the factory with an air lock in the cooling system, and owners notice a sudden drop in coolant level when the air finally works its way out into the expansion tank, and coolant flows back into the system to replace the air lock. Thinking about your original post, if you do have a (large) air lock, that could explain the drop in coolant level you’ve been experiencing.
Have you had your cooling system pressure tested for leaks (they might not always be visible, depending on where they are if you do in fact have a leak), or have you noticed any coolant odours from the engine compartment when the coolant’s up to temperature and under pressure?
Another possible cause of poor (or no) heat output from the heater is a blocked heater matrix. There‘s been a number of recent discussions on various VAG forums (VW Golf and Seat Leon) where the sealed bag containing silicon beads and located in the cooling system expansion tank has been known to split. It‘s there to help prevent corrosion damage to the aluminium parts of the cooling system, and to prolong the life of the coolant If your car has one of these bags, I think the expansion tank will be marked ‘Mit Silikat’ on the outside, about halfway up. If the bag splits, the silicon in the bag can find its way into the heater matrix and block or partially block it, the result being poor heat (or no heat) output. Flushing out the heater matrix to clear the silicon doesn’t seem to be effective, and it’s usually necessary to replace the heater matrix.
