2006 coolant running out quickly

So the other day I went to check my coolant level, there was absolutely 0 coolant so I topped it up to the max. A week later I checked it again and to my surprise it was fully empty. I have topped it up again to the max and also did not notice any drips of coolant on to the drive and no leaks underneath the car. However, after topping it up to the max level I can hear a bubble every 15-20 seconds is this normal? I have also connected my obd2 device and it came as code p0598. This disappeared immediately after putting in coolant. Do I have a leak somewhere I cannot find?

Hi

Bubbling is not normal.

No evidence of a leak could well be the head gasket failed. Seems to be quite common on the petrol engines

I've already replaced head gasket ☹ also if my coolant sensor is defective, can that increase consumption of coolant?

I described it as a bubble earlier but this is inaccurate, it sounds more like for example, topping up engine oil where the neck of the container is being poured bit by bit but at a slower pace, it feels
and sounds like coolant is going into a tank

Jjb0800 wrote: ↑Tue Jan 18, 2022 4:06 am I've already replaced head gasket ☹ also if my coolant sensor is defective, can that increase consumption of coolant?

Did you refill the coolant following our guide?

tips-for-any-citroen-c3-f8/coolant-t40.html

Yes I am using the original citroen antifreeze which is blue and ready mixed

The actual instructions on how to fill the system are also on the post, maybe a few replies down. The procedure ensures there is no air left which could explain where your coolant topping up is going.

I have checked level after 24 hours and has gone from max to minimum within a day.

I see, I had no idea that you cannot just pour it in as air will get in the system, is there any apparatus I can buy instead of using a cut out plastic bottle?

There is a proper Citroen tool shown in that topic, but a plastic bottle is much cheaper and works just as well.

If you didn't fill the system properly, you could easily damage the head by overheating and would need to do the head gasket again.