A4 tdi Leaking coolant. Should I just change o-ring or the whole flange?

[vTek]

Hi guys


I have been getting a small water leak for a while now on my Audi A4 1.9 tdi (1997). It just means a top up every week or so with about 3/4 litre of water, sometimes less. I have found where the leak is. It is from the coolant flange which is connected to the cylinder head block near back of engine. it seems like it might just be the o-ring that seals it. However, I have read that the flange them selves actually can start cracking/leaking, I will not be 100% sure until I remove it all. But I was thinking of just replacing the O-ring (few quid from Audi). Is it worth changing the flange as well?

Any tips on how to do this as well would be appreciated. The part number for the flange is: 028 121 113, and the o-ring sits inside this against the engine block.

Thanks in advance for your help

[vTek]

Any body? I need to know today, so I can get the parts ordered...

[adamss24]

It might help if you put some radiator stop leak from local Halfords shop. It is in blue bottle and it works a treat.

[vTek]

I thought these liquids can more damage in the long run?

I would rather do a proper job to be honest....

[vTek]

There must be someone on here who can advise me...

...anyone??

[audimad]

If it were me, i would change the lot at the plastic can get brittle with age and maybe break on re assembly. Also they are known to warp so you may never get a seal on the old one and have to do the job again to put the new part on you should have done at the time

[vTek]

Thanks Audimad...much appreciated.

I will order parts today...

[vTek]

Done!!!

After 3 hours of hard labour (I took my time), sore hands (from trying to put back one of the hose clips back on), I managed to do it.

For the first time I reluctantly worked on the cooling system on my car (electronics I am fine with, as its cleaner ). I am always cautious doing these kind of jobs as it looks quite delicate with all them hoses

At first I took off wrong hose from bottom of rad...I think I took off the turbo pipes, as nothing came out of it except a drop or 2 of really thick oil?? Then I just decided to follow the pipe from water reservoir as further down as I could, then removed the hoses going to the flange. Flange was a bit tricky as all the injectors are around there and I didn't want to damage anything else. Just had to make sure all the plugs/sensors were out of the way. I took my time doing everything as I didn't want to break anything else.

With all the water finally out, I then flushed the whole cooling system with hose pipe.

Next step, clean the crap off the engine head (where flange will go) with a blade, was quite a bit of scale build up on there. Then putting everything back together, pretty straight forward, so I thought, but I just couldn't get my pliers to get around the hose clip, tried everything, then after about 45mins of trying, managed to find some larger opening pliers to grip.

Then I made 2 parts to 3 parts mixture of G12 coolant from Audi. I think I made too much (used both the 2 litre bottles, I now have 2 bottles of mixed coolant left over...is it ok to keep this for future??).

Replenish stocks, test, and I am away...I will find out today (after engine has dried up from draining) if it is all ok.