Coolant

Only an OAT (Organic Acid Technology) Coolant and Antifreeze is used in the C3.

It is generally identified by its bright red/pink colour.

If the colour of your coolant is brown, it probably was red/pink but now includes bits of corroded cooling system - flush the system thoroughly and refill with red OAT at the correct concentration.

If the colour is blue , don't mix red/pink with blue. Start by draining and flushing before refilling with pink/red OAT

You may see yellow which is a HOAT or hybrid OAT.
HOAT is more compatible with other antifreeze types and is not fitted in the factory, but often sold as an after-market 'fully compatible' coolant because it will be unlikely to cause problems if mixed with other coolants.

Colours are only really only just a guide as there is no industry standard for colours so they can not be fully trusted if you don't know the history of the coolant. The best advice is to flush and change if you are unsure of the history of the coolant as a preventative measure.


For concentrate you must mix with deionised water. a 50:50 mix is often sufficient but it is important not to use tap water as this may (and probably does) contain unhelpful contaminants that could reduce the life or effectiveness of the coolant.

You can get the RED OAT concentrate in 1L and 5L quantities.

This is 1L Xstream G30 Concentrate and is suitable for the Citroen C3. A smaller quantity of concentrate for topping up.



5L Xstream G30 Concentrate is ideal for a flush or drain and refill of the complete cooling system of the Citroen C3.



Use this De-ionised water to dilute concentrate coolant (50:50) for any of the ones listed above.




Convenient 5L Xstream G30 Ready Mixed is a larger quantity of a ready mixed coolant. Taking the guess work out of mixing your own.


The Citroen C3 cooling system capacity is 7 litres.

If you want a 50% solution of antifreeze, you will need 3.5L of de-ionised water and 3.5L of antifreeze concentrate to fill the system from empty. Its worth having more to allow for a 1L 'header tank' attached to the expansion tank, this is full and the engine run till hot to ensure all the air is purged out if the system has been drained and refilled with the 7L. A header tank is not required for just 'topping up'.

Obviously the ready-mixed will not need any dilution and you will need at least 7 litres of that for a refill of the complete cooling system from empty.





The black coolant pressure caps don't last forever and it may pay to renew the cap (available here) before it fails and while refilling the system on an older car.

C3 2002 Coolant filler location shown near the Screen Wash filler neck.
To check the level of the coolant in the reservoir ensure the engine is cold and the level of the liquid (pink) is between the MIN (minimum) and MAXI (maximum) marks on the plastic body.

Cant understand this buis with the header tank. According to Haynes you fit this befor filling so where do you pour in the coolant etc. In the past i have done many coolant changes without any of this not even using the bleed outlets. The method used was to fill up leave the filler cap off start the engine allow to heat and keep squeezing the outlet pipes, never had any problems. Any further advice would be of help.

Using an header tank to refill the cooling system of a Citroen C3 after draining it for repairs, a scheduled maintenance change of coolant (every 5 years or so) or due to contamination with blue antifreeze or some other contaminant.

The header is not required for topping up, only if the system has been drained of coolant.


This header tank was made by cutting off the bottom of a coke bottle, the neck is a bit too small, a bottle with a wider neck would have made it easier.


This is part of the Citroen workshop tool to act as a header tank, a long neck adaptor fits between this and the expansion tank which all screws together quite nicely.


The full header tank provides a 'head' of coolant to help expel trapped air in the system after emptying the cooing system. Its important to make a good seal that can withstand hot water for 25 minutes, wrap pvc tape around the neck of the bottle or some gaffer tape around the join if your bottle doesn't seal well to the expansion tank filling point.

There are syringes (here) and rolls of gaffer tape (here) on eBay that can be very useful to have to hand with this refilling job.

The excess OAT Coolant in the header is not used in the cooling system and will need to be returned to a sealed container and saved for topping up or disposed of safely. Remove any excess coolant in the expansion tank, a length of PVC pipe on the syringe makes this very easy

With the header tank to the fill level, close each bleed screw as soon as the coolant flows without air bubbles. Run the engine until the fan cuts in, then cuts out and cuts in again. This should allow the trapped air to circulate past the thermostat and allow the system to expel any trapped air. Different engines fitted to the C3 have a different number of bleed points in different locations, but look for one on the heater pipes and one on the thermostat outlet housing.

Still dont get it. The expansion bottle is well above the thermostat on my 1.4 eight valve engine and the added expansion bottle just takes things further up the line so to speak. To play safe you could fill the system a little higher.

can i know what is the problems i will face if i use wrong coolant or just use water ?

My car is C3 petrol 2003 Automatic gearbox , can i know also what must i refilling the cooling system in my car ?

ahmedalmulki wrote:can i know what is the problems i will face if i use wrong coolant or just use water ?

My car is C3 petrol 2003 Automatic gearbox , can i know also what must i refilling the cooling system in my car ?

If you use just water, the system can corrode. There are additives in the antifreeze and coolant that stop the corrosion.

Water has a freezing point of 0c but antifreeze will freeze only at sub zero temperatures. If the coolant freezes it expands and can crack or split the system and there will be nothing flowing if its frozen.

If you mix the wrong coolant with the right coolant they can react and turn into a gel or loose their anti corrosion properties and possibly the anti freezing properties.

The correct OAT coolant (also here) is shown in the first topic, use either concentrate and mix it with distilled water to dilute it or use ready mixed.

hello everybody!
i have bought 5litres of synthetic antifreeze liquid for my c3 1.4 diesel 2014.
do you know if i need more than 5litres to replace the antifreeze liquid of the whole cooling system?
thank you!

johni41 wrote:hello everybody!
i have bought 5litres of synthetic antifreeze liquid for my c3 1.4 diesel 2014.
do you know if i need more than 5litres to replace the antifreeze liquid of the whole cooling system?
thank you!

Hi johni41

I don't know for the 2014, its a bit new to be changing coolant, but all the previous diesels took over 5L for the full system, from 5.7 to 6.2 L. So I would expect the newer engine to be similar.

thank you!
i spoke to my mechanic and he said me that we will need 7litres so with your opinion i think that i have to buy 2-3 litres more...
thanks again!