Hi there
I have a problem with my 2014 2.0 TDI with coolant, from time to time, once a month at starters ( I have it a year and a half for now) I had to top up coolant, OK, cap off, pour in some g13 and it's ok for a month.
But it startet "loosing" coolant more frequently, and I came to a point where I made 40 km, and coolant went from above max to below min, just enough to activate dash warning.
I've read sooo many topics about heater matrix problem, so, I went to shop and bought myself heater matrix, 5L of coolant concentrate, expansion tank and a lid for it.
Just to say, coolant wasn't changed from 2014, so it was original coolant in there.
I've flushed the system, also run presurised tap water for pressurised cleaning, then with deionised water, changed tank and a lid.
I didn't change heater matrix, because it wasn't clogged at all, heating is great, tried cleaning it with hose water, it was all good. (and I also bought the wrong one, but, that doesn't matter now, because my heater worked before too)
Now, I would like to know, what is capacity of coolant system, I poured in almost 7 liters of coolant.
Second thing, I've noticed that coolant went down again, ok, maybe there is an air lock, but when the car was cold, I openned the lid, and coolant returned to a half of min/max mark.
Today  I openned the hood, when I got to work, coolant was little below minimum, so I left it to cool down, and when it was cool, I openned the lid and level rose above max mark for a 5 mm.
Did any of you have such problem? Because Google is not very helpful friend in this situation
Just to notify, HG is ok, we've already checked that. Some mechanics said to me that it could be head crack, so when the engine is cold, everything is ok, but when it gets warm, alluminium gets wider, and crack lets coolant to intake or exhaust valve.
Car starts great, goes even better, oil is clean, there is no visible leaks, no loss of power, it hasn't any other flaws other than this loosing and regaining coolant.
Thanks in advance ;)

Anyone?

Its a gradual failing of the waterpump in the car. The TDI's use some coolant when doing regens; its perfectly normal to top up the coolant header tank after a good hot regen process. However, what you describe is not normal. It sounds like a waterseal in waterpump is gradually failing and is beginning to leak water. 

 

You need to get this sorted now, because otherwise it will fail catastrophically. In the morning, get under the car and look for a damp patch where the waterpump is located. 

 

Time to do a timing belt and waterpump Im afraid. Ignore your mechanic....and you will also need a coolant change with G13. If your header tank has 'Mit Silikon' on the side, you will also need a new header tank (unless you are lucky enough to have the version where you can fish it out by hand).

EGR cooler is a possibility. When you open the expansion tank cap with completely cold engine, is there a release of pressure?

The other possibility is the expansion cap itself. They also fail.

Waterpump changed in August, it failed, so we've put the one without that sleeve, header tank and its lid was also changed also with g13 coolant a few days ago.

 

Yes, Wino, there is a small pressure and coolant then rises a bit.

That's consistent with combustion gases getting into the cooling system somewhere. How was the HG checked? 

Is it possible to bypass the EGR cooler (link together the two coolant hoses normally attached to it) to see if that causes a change of symptoms?  Not sure how difficult it is to do this on your engine.

Well, it shoudn't be so heavy to do this, I just have to get under the car and sort it out.

Do you think it could be cracked?

It would be a good thing to check. 

I'll try to test that.

So, to clarify, is it even possible to get a crack in head on cr engines?

Just to make me calmer, you know..

I don't know, sorry. 

Question, does anyone know what is diameter of tubes for egr cooler, so when I start doing bypass proces, I come well prepaired?

Hey, I didn't managed to bypass cooling for egr cooler, but, I managed to use endoscopic camera, and this is what I managed to see in the area of solenoid valve for egr.
Is this maybe proof that egr cooler is broken/leaking?

EGR valves tend to be sooty and have carbon in them. It looks like there has been some kind of 'washing' effect. I don't like the look of the green tinge inside that valve either. Do you have green or red coolant in your car? If Green, then it is definitely getting into that valve. This puts me in mind that you have a Coolant leak in the engine block and that coolant is potentially getting into the combustion process and into the EGR valve itself. 

I have red coolant

I will try to take off o2 sensor on ionisator, to see if there is some kind of liquidation

That just looks like oil to me, but that used to signify a leaking egr valve.

 

If the level is being pulled down then returning, I would ask by how much. If not much then it could just be the pump pulling an effective vacuum on the line. 
As they’re cheap a new tank lid would be my first check.

 

If it is going down a lot then up, I would still do the cap just to rule it out, but also deal with the egr cooler and find out why is has the oil leak. Also make sure all breather pipes are clear.

 

Far from a complete list but worth checking.

Coolant pump is changed this year, coolan expansion tank and cap are changed too, it's doing the same thing with the old ones and the new ones too.

I've seen that there are numberous one-way valves on some of the tubes, does anyone know how many are there exaclty? 

 

How do you think egr leaking oil? There aren't oil lines connected to egr, are there?

The EGR is definately seeping oil, as that's oil over it.

The purpose of the EGR is to effectively make the car breath it's own farts, so you have dirty and oily air mixing in there (as well as new air).

 

The solonoid valve has been known on older cars to fill with crud (oil and soot) and also have seals deteriorate, which then leads to oil leaking past and out.

It's not a oh my god thing, just something which should have attention paid and either cleaned internally and externally, checked and kept and eye on or replaced.

 

There are no oil lines that I am aware of and on the older cars it was just diry and clean air. On the newer cars there are EGR coolers which obviously have pipes from the coolant feed.

 

I didn't think the water pump was failed, I just wondered what the level drop was, because if it's tiny (a couple of mm) I would just keep an eye on it and see if it does it both cold and warm.

 

On the one way valves, I am afraid I have no idea, but TBH if they had failed you'd know about it pretty quickly.

 

The lack of sleeve on the new pump could also cause if it's just a small drop, as the system isn't designed to have significant flow until you have some hot coolant.

If you have flowing coolant without warm coolant (which has expanded coming back) then you might notice a very small drop and rise.

 

Again if it's a big drop, I'd probably talk to a garage, as the cost of something serious would far outweigh the cost of a garage visit.

I fount the leak...

It was charge cooler...

 

Are you sure thats not just oil? I have suggested the charge cooler before to people with mystery leaks but have never known anybody have one fail but it is perfectly plausible.

I didn't managed to get a good picture with good color, but this liquid is as pink as new coolant, and since there's a lot of oil inside too, the difference can be easy to see..

My charge cooler has number 04L 129 766 Q, and I've found on the market 04L 129 766 K, is there any significant difference with them?

Chargecooler changed, we will se if it's going to be better

Hello

@yomarkina the chargecooler replacement solved your problem?

thanks