Replacing Anti-Freeze/coolant

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zx bomb
Posts: 8
Joined: 08 Feb 2001, 01:50

Replacing Anti-Freeze/coolant

Post by zx bomb » 28 May 2001, 22:24

Citroen ZX 1.4i 1997.
Despite having the Anti-freeze for the past 3 months,I have not got up the courage to drain and refill the system mainly because the Haynes manual is confusing and secondly I've never done it before and I don't know about you, but the first time for a new job is always worrying.
1:The drain plug on the bottom of the radiator seems very stiff,is it anticlockwise to allow water to drain?
2:how many vent points are there?I can see one at the Heater matrix and one on the top of the radiator,I suspect theres lots more!
3:Should I flush the system with a hose pipe into the filler cap? Or should I reverse flush? If so which hose should I take off.
Finally do I need to make myself a header tank to refill the system?
Any helpfull advice based on your experiences would be appreciated.

Chris Peddie
Posts: 50
Joined: 29 Apr 2001, 17:04

Post by Chris Peddie » 28 May 2001, 23:30

I don't know anything about ZX petrols(!), but maybe this will help you:
Anti-clock should undo the plug (the one on my xantia was pretty stiff).
As far as I know, the radiator should be reverse flushed (usually hosepipe into bottom hose of rad) and its a good idea to flush through the engine block as well before refilling to make sure its all clean, although this might need the thermostat removed.
Diesels also have a bleed screw on the top of the thermostat housing (need hex key for this). I guess yours might have something similar.
I think only xantias need a header tank, but, I could be wrong.
I'm sure someone will correct me if any of this is wrong, but hopefully these ramblings are of some help,
Cheers, Chris

donor 2019
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Joined: 15 Mar 2001, 00:41
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Post by JohnD » 28 May 2001, 23:54

Hi - Yes! all the above is correct, but it is as well to make yourself a header tank. I find I need one on my Xantia and also on the family's BX and Pug 205. I've made mine from a four pint milk carton with the bottom cut out and an inch or so of old radiator hose between the can top and the rad filler. Once the system is full, keep water in the header tank with the engine ticking over as you bleed the air. The drain plug turns anti-clockwise to loosen and allows the water to escape without needing to be completely removed. All the best!

Dave Burns
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Joined: 14 May 2001, 05:30
x 2

Post by Dave Burns » 29 May 2001, 00:13

Yes you need a header tank, some of the hoses are at a higher level than the expansion tank, early models of the 205 had two bleed screws on the thermostat housing,don't know about the ZX i've only seen later versions with the fuel filter on the thermostat housing, the only other screw that I know of is on the hose from the heater matrix, this is a plastic screw into a female metal thread, be careful not to cross thread it, pour the water/antifreeze mix in slowly.
Don't be afraid of it, the only problem you will have is going to be finding something to make the header tank from that provides a good seal.
Regards Dave

zx bomb
Posts: 8
Joined: 08 Feb 2001, 01:50

Post by zx bomb » 29 May 2001, 01:04

You Guys are the best!!!
Thanks a lot for the information.
I didn't realise that there was so many knowledgable and helpful people around.
I now much happier and have a far better idea of whats involved.
The Haynes manual states that I need to replace the sealing ring on the radiator bottom hose.I've not seen in any of the mail order catalogues this seal available,and theres no local Citroen close to me .
Anybody put the hose back on with the old seal?
Thanks Ian (zx bomb)

Dave Burns
Posts: 1916
Joined: 14 May 2001, 05:30
x 2

Post by Dave Burns » 29 May 2001, 02:44

Hello Ian
Those O rings can go stiff after a period of time, they mould themselves to the shape of the part that they have been sealing against, once they are disturbed they will more than likely leak if re-used, then you will have to go through it all again, antifreeze is very searching liquid, give it half a chance and it will be out, might be a hassle for you to get those seal's, might be a bigger hassle if you don't.
Take care

zx bomb
Posts: 8
Joined: 08 Feb 2001, 01:50

Post by zx bomb » 03 Jun 2001, 22:35

I would like to add a final postscript to this subject .
I have completed the job and as someone said it wasn't as scarey as it first seemed.
If I could give others the benefit of my experience please make a note of this IMPORTANT POINT.
I went to my nearest Citroen dealer to buy the bottom hose 'O' ring as the Haynes manual insists that this must be replaced after disconnecting the bottom hose from the radiator.Luckily it was a Saturday Morning and instead of the normal storeman a Mechanic was covering the spares counter,he was horrified at the suggestion of removing the bottom hose for flushing the engine/radiator as he said .
A:It was a swine of a job to get off,and more importantly it wasn't required as the job could be done by flushing from the expansion tank or reverse flushing from the drain plug.
B:He also said that he had never removed a bottom hose without destroying it in the process so make sure that if you do have to take one off you've got a spare one on hand.
anyway I drained and flushed without any hassle and now have a refilled ZX.
Good luck and thanks to every one who helped