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C4 Coolant Drain and Flush

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Sat Feb 28 2009, 06:07pm
Citroen C4 1.6 petrol 05 plate.Can any fellow members advise foolproof way of draining,flushing and refilling coolant on the above vehicle.

I am reluctant to attempt this as have heard that they are difficult to bleed of air when re-filling, this may be a myth or vicious rumour.

Any advice would be appreciated.

Sun Mar 01 2009, 02:01am

Member No: #1
Joined: Aug 07 2006
Location: Northumberland
It's no myth or vicious rumour, they can be a real pain.

When I had my radiator changed (the gasket between the cooling matrix and header failed) it took an hour to get the air out of the system and that was by a trained Citroen Technician

As a ' Premier Member' you can access the official Petrol Engine Radiator Air Bleeding Guide (The diesel
engine guidess are also available)

It just needs a bit of patience when you refill, get the engine running once you refill and run it until the thermostat opens keeping an eye on the header reservoir and topping up as the air eventually passes through.
Sun Mar 01 2009, 08:27am
Thank You for your prompt answer,

Will try the nightmare this week-end if i get the time and will post on how easy/dificult it proves to be.

Thank you
Sun Mar 01 2009, 10:29pm
there is a bleed valve for air covered by a plastic nipple below the header area near the airbox

cut down a lot of steps compared to the guide
Sat Dec 11 2010, 04:00am
Member No: #7028
Joined: Jan 11 2009
Location: Croatia
Kevin, have you managed to drain and refill the coolant system? I'd like to give it a go because I need to put in some anti-freeze fluid, currently there's only water in it.

Is there a guide for non- premier members?
Sun Aug 12 2012, 07:52am
Member No: #10602
Joined: Aug 11 2009
Location: N. Ireland
Hi Just noticed this post.. I downloaded the guide but there are some unclear parts.. Can someone show/direct me to where the engine drain screw is on the cyl block.... From my looking about on the site I think it is behind the engine (towards cabin) near the air filter??? Could someone verify this? Also the bleed screws..I have no idea where the heater matrix bleed screw is??? I also assume that the coolant outlet housing bleed screw is somewhere near the air filter region?? I have serviced most other parts of my car but this one has got me confused and im scared of getting into an unnecessary tangle that would cost £25 at the garage!!.. Any easier alternatives would be great too!
Tue Nov 13 2012, 12:01am
Member No: #19214
Joined: Apr 11 2011
Location: Harties South Africa
Obviously you already found success, for those who also searching for that screw. It's on the heater matrix hose against the firewall.

I spent some time looking for it, with the battery in its very difficult to spot.

Took a pic for all interested.

4 User said Thank You to Zedd for this Post :
 hchakarski123 (12 Dec 2016 : 03:45) , Krazz (27 Mar 2020 : 04:26) , Heinrock (15 Jun 2021 : 02:33) , geopug (23 May 2023 : 08:45)

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