A2 coolant leak, help required

SzeBen

Member
Hello all,

So I have a 1.4PD A2, and the coolant is going to somewhere. First it was the expansion tank, it was visible. But now, I cannot locate, and cannot hear any leaking when I put the coolant system under pressure (1.7 bar). The pressure slowly goes down, and no sounds or coolant in the engine. So im asking the community, what can be the possible problem? Im not really familiar with this engine.

Thank you!
 
It has got to be going somewhere. From the expansion tank it can end up:

1. in the heater matrix behind your dashboard
2. in the engine block somewhere

You just have to follow it in one way or the other. I'd check the heater matrix, coolant pump, sump or even where the cylinder head joins with the block. Remember that some leaks are not easy to trace if they are in a hot place and the coolant evaporates quickly.
 
Thank you guys, I think its cylinders too. Expansion tank and cap was replaced, I modified the VW polo one (cheaper :D )
 
Perhaps not cheaper if it is the issue. How do you know the Polo cap operates at the same pressure as the A2 one?
 
Evening,

I’ve recently had a scare that the head gasket was failing in Project OEM as couldn’t find an obvious leak anywhere and was adding half a litre of coolant every could of weeks. This has been going on for a few months whilst I was saving up for a four figure repair bill.

Upon further investigation it was evident that the top of the gearbox was damp. It turned out that the coolant union/manifold on the lower left of the engine was at fault. The giveaway was that the top hose on this union/manifold was wet and that the item had failed. Replacement part was ordered and fitted. No drop of the coolant level has occurred for some 800 miles but monitoring just in case.

This may well not be your issue but certainly worth getting a torch in that area and look from every possible angle as I didn’t notice this for some months when checking the level weekly.

Hope this helps.

Kind regards,

Tom
 
Another area to check is the coolant manifold bolted onto the block just below and in front of the tandem pump. If there has been a leakage from the tandem gasket then the fluid runs down the block and eats into the coolant manifold. Once it reaches the internal seal this is quickly damaged and then leaks coolant. The integrity of all hoses is vital and the smallest of pin holes will leak a surprising amount of coolant when under operating pressure and temperature plus vibration.

A messy way to check for coolant leaks is to clean everything then apply talcum powder to all the joints and sealing areas. Leaks will show up in the talcum. Please do not use flour for this as the resulting mess will be nearly impossible to get off any time soon. Had to pressure wash the engine bay on a Golf 4 times to get only the worst of it off!!!!
 
Thank you guyy, I had a little accident so it will take some times to start check it, along with the door open problem (posted an other thread earlier). Will report you back on both topic. :)
 
Little update:

So the car is pushing out all the coolant through the expansion tank (the tank and the cap is good). Hoses are hard etc. So its for sure Cylinder head problem. Will take it off and send it to a shop, then put it back. So far this car is a disaster but im positive it will be a car one day. :)
 
Have you checked the Webasto heater has not failed internally and that is over pressurising the coolant rather than head gasket failure. Not saying it is not the head gasket but a cheaper repair.
 
Actually I forget to test it. I dont understand how this heater working yet. How it can push out all of the water?
I ran a full diag when I bought the car but dont recall any errors related to webasto (maybe its info for you).
 
Actually I forget to test it. I dont understand how this heater working yet. How it can push out all of the water?
I ran a full diag when I bought the car but dont recall any errors related to webasto (maybe its info for you).
Often, if the head gasket is faulty, there are traces of oil in the cooling system, and of course oil contaminated with water.
 
I was having the same symptom of a headgasket faillure but without any other telltale. After having fixed a tonne of leaky joints/parts/etc., I soon observed that the expansion tank is not exactly level (!!!) on ours (1.6) and I just let it push out all the coolant it wanted. The coolant has now settled 2cm below the minimum mark and has not moved ever since and I keep an eye on it religiously. It has now been 4 weeks and th elevel has not moved. I do have some hairline leaks on the gauge sensor and the radiator but they are really vapour-like as they do not even get your finger wet when touched.

Get the heater checked (I have no experience on these sorry) and as long as you can see coolant in the tank it should be all right (probably). We get a solid 50mpg on ours at the moment on a daily 25 mile roundtrip to work.

Which coolant bottle did you use if I may ask? @SzeBen
 
Is the cap new as I asked back in post #4? Does is seat tightly and seal tightly in the incorrect expansion tank? Is the fluid in the expansion tank the same quantity as would be in an A2 tank? Are you using the correct coolant at a suitable concentration?
 
Is the cap new as I asked back in post #4? Does is seat tightly and seal tightly in the incorrect expansion tank? Is the fluid in the expansion tank the same quantity as would be in an A2 tank? Are you using the correct coolant at a suitable concentration?

The tanks are the same for the 1.6 at least, the mounting points being the major differences and the tank barbed connection locations.
 
Doesn't it make you stop and think when Audi used a different part number for the A2 expansion tank compared to the Polo?

A2 expansion tank 8Z0121407C , cap 1J0121321B and seal 1H0121687A


New genuine expansion tank available from Audi Tradition for about €45 but comes without a cap.
 
The tank is really expensive here comared to other car expansion tank. and I simply dont wanna pay that much. :/ 80 euro here (vat, shipping, etc). So I put a polo 1.4pdtdi one with a longer hose. Need a little modification and thats it. There are a lot of things which can be used from other cars. For example I Just did the bushing (where the control arm sits) with a 2009 Audi TT one, and its perfect. :)
 

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