Coolant Leak Diagnosis: Early Signs & Solutions

Hi there,

My Audi A6 2.5 TDI, manufactured in 2000 and with 120,000 km on the odometer, has a slow coolant leak. I bought it used two months ago, and during that time (having driven approximately 3,000 km), it has lost about 1 liter of coolant.

At first glance, I would suspect head gaskets – but at 120,000 km? And shouldn't you see small bubbles or foam in the expansion tank when the engine is running?

Does anyone have any other ideas about what it could be?

Thank you very much!

Chris.

Hello,

Is the cooling system leak-proof? To check, it should be pressure tested.
Otherwise, please check the coolant reservoir to see if there's anything on the surface.
If you see an oil film, then ZKD.

As mentioned in other threads, ZKD (head gasket) damage can be so subtle that you might not find anything initially when inspecting the vehicle in the workshop. However, there could also be a leak elsewhere, such as in the radiator. To check for this, you can add a UV-reactive dye to the coolant and, after some time, inspect all potentially affected parts using a UV light.

Hello,
At my AFB, the head gasket was replaced at 14,000 km (no zero is missing ), due to coolant loss, and after that, everything was okay.

Regards,
Dieter.

Thanks for the information! A timing belt replacement after only 14,000 km? That's quite extreme.

I did a little bit of asking around. The people I spoke to said that a timing chain issue (ZKD) with an AKN engine at 120,000 km is highly unlikely.

Therefore, I think this goes back to my 'good friends' at the VAG authorized workshop. After purchasing the car, I immediately had the timing belt replaced. During that process, they couldn't remove one screw from the viscous coupling cooler and then heated it up. Bang. The resulting damage amounted to 350 euros in material costs (bracket, RI disc, cover, clutch). The coolant was also completely replaced - something seems to have gone wrong there. And I had to pay for that too.

Now the question is - should I give them the car for further repairs? I'm not really ready to tackle the AKN myself (yet)... But honestly, I wouldn't even trust that workshop with my bicycle.

Okay, the 'slow' leak is over. Since this morning, it's been flowing steadily, about half a liter in 3 hours. Well, I'll take that as good news; at least now the leak will be easier to find. I guess I have to take the car to my special 'friends' at the VAG workshop for further repairs.

Therefore, I think this probably goes back to my 'good friends' at the VAG authorized workshop. After purchasing the car, I immediately had the timing belt replaced. During that process, they couldn't remove one screw from the viscous fan coupling and then heated it up. Bang. The resulting damage amounted to 350 euros in material costs (bracket, rotor disc, cover, clutch). The coolant was also completely replaced - something seems to have gone wrong there. And I had to pay for that too.


Okay, so what? The damage they caused? My dear sir, I would definitely get out the chainsaw! Is it my problem if the screw won't come loose?
In situations like that, you either need to use your ingenuity and find a solution (e.g., drilling, chiseling, whatever is appropriate), or if nothing works, inform the customer that there's a problem.

CU Gremlin.

Yes, how now? The damage they caused? My dear man, I would definitely get the chainsaw out! Is it my problem if the screw won't come loose?
In situations like that, you either need to use your ingenuity and find a solution (e.g., drilling, chiseling, whatever is appropriate), or if nothing works, inform the customer that there's a problem.

CU Gremlin

'Yeah, you make it sound so easy. Of course, I got caught in a tricky situation, but there's nothing I can do about it now. Ultimately, we agreed that I would cover the material costs and they would cover the labor costs. I also immediately said that this could end up in court. However, that didn't impress the service manager. Now, I've first submitted it to the arbitration board of the Chamber of Crafts, let's see what comes out of that. But potentially, VAG Service might also get involved; I heard from a friend that the workshop has already received a warning.'

But let's get back to the coolant issue – I then took it to the same workshop (for possible further repairs), and they said that some drain valve on the engine block was defective. The material cost was €17, and the labor time was €100. Because I couldn't find another workshop so quickly (and because they made an effort this time by offering a free replacement car, etc.), I told them to go ahead and do it. However, charging 1.5 hours of labor for something that probably takes a maximum of 30 minutes is quite outrageous.
Okay, so my need for VAG-approved workshops is covered. I've found a 'budget'-friendly workshop nearby that seems competent and affordable.

Hmm, is there anyone else here who disagrees with the workshop service? I have to say that I've been to two or three workshops so far and haven't been satisfied with the service.

Best regards, WarLord.

'Quote:'
Hmm, do we have another person here who disagrees with the workshop service? I must say that so far I've been to two or three workshops and I'm not satisfied with the service.


Hello, I have the same level of trust in the workshops around me...

I was having problems with my coolant temperature.
https://community.dieselschrauber.org/en/viewtopic.php?t=4172 ) .

While I was at the workshop buying a new thermostat and inquiring about installation costs, I was quoted approximately €90 for labor (including parts). Knowing the location of the part, I considered having it installed there. However, when I asked another dealer, they quoted €210! I had the first shop send me a written estimate, which came to €320 (a significant increase from the initial verbal quote of €90!!!).
[/quote]

Okay, this is going to be a bit off-topic, but what the heck. I think there are certainly many people who are happy with their workshops and wouldn't post about it here. But I have to say that the standards of behavior in Germany have become quite rough.
I lived in Sweden for 5 years, and not a single dishonest thing happened. No inflated bills, no problems with workshops or craftsmen. Verbal cost estimates and agreements were always honored. I had become so accustomed to it that I thought this was simply the norm. The only downside was sometimes the extremely long waiting times: 'What? You want your car fixed this week? Ha ha ha. I might have an appointment in 3 weeks.' (No exaggeration, this actually happened.)

The three months I've been back in Germany have given me quite a few gray hairs. It's no wonder that all the craft businesses are complaining – with the service and quality offered, it's often better to just do things yourself. So far, it's mostly been frustrating; hardly anything has been done to my satisfaction: problems with workshops, inflated and incorrect invoices from everywhere, poor quality, and so on.
Okay - a commendable exception: An elderly electrician from the shop around the corner fixed a 400 V line that I had drilled into. He came by quickly, took 10 €, and got everything sorted out. It seems that this kind of thing is now a rare occurrence here.

Oh, the faucet.
Yes, it always breaks down if you ever park on a grassy area.

Seriously: I hope you didn't misunderstand the description of the defective part when talking to your mechanic. What does the invoice say?

Hello Chris!

I'd also be interested to know what they actually exchanged. I have an AFB engine and have been slowly losing coolant for two years now. It's not more than a liter every six months, but I still don't think it's quite normal.

I also don't remember parking on a blue lawn .

DENNIS

Okay, here are the parts:


Coolant drain plug on the engine block.
059 121 481 C pipe.
077 121 437 Sealing ring.

It doesn't look like a drain valve. But I haven't misheard anything, I'm sure of that.

Does anyone know if they are located near the viscous fan? They were deformed, which, according to the service technician, had never happened before. I'm not quite sure what to make of that.

Here's something else - I was actually pleasantly surprised. The service master greeted me with the words, 'Oh, hello, I just read your arbitration request, and it seems like you probably don't have a chance.' Well, at that point, I thought, if he wants war, let him have it. Yesterday, I sent an email to Audi. Surprisingly, someone actually called me today. They said they can't do anything legally or financially (understandably, the workshop is independent), but they want to keep an eye on the situation. It doesn't really help me much, but I thought it was very nice.

Chris.

Okay, so what? The damage they caused? My dear sir, I would definitely get out the chainsaw! Is it my problem if the screw won't come loose?
In situations like that, you either need to use your ingenuity and find a solution (e.g., drilling, chiseling, whatever is appropriate), or if nothing works, inform the customer that there's a problem.

CU Gremlin

Okay, I just finished a meeting with the Chamber of Crafts. I got the impression that it went quite fairly. Initially, those present were quite critical of the workshop. However, they (and I) could understand from the explanation that there was no other way to loosen the screw (it was an Allen/Torx screw, hardened, difficult to access, etc.).

We then agreed that the workshop and I would each pay half of the damage because the workshop didn't inform me beforehand.

P.S.: Just to be sure - does anyone happen to know if the Viskoterm fan on the AKN is actually attached with a screw made of talc and not with a hex bolt? Because if it were a hex bolt, the workshop would probably have to charge quite a bit more...