Slow, slow coolant leak or loss (Brand New 2017 Audi S7)

[Frenetic]

So I've been monitoring coolant levels in my car recently.

Go back about one month and I noticed my coolant level in the overflow reservoir was nearing the minimum line on a dead-cold engine (car mileage about 3000 miles). I vaguely remember it was just above the second down arrow that shows the Min line. Again, vaguely. So, after Thanksgiving, I go buy some coolant and distilled water, put a 50/50 mix in a metered plastic fill bottle and filled it back up to the top of the bottom arrow. From the Min. line to that arrow is roughly 8-9 fluid ounces.

So, fast forward to today (+1000 miles) and I recheck (again, same dead-cold engine condition) and sure enough it has dropped slightly. Maybe a few ounces, but it's definitely below where I set it at as I took a picture of the level when I refilled (see below).

I looked everywhere, including the coolant lines and for leakages around the tubes to the overflow reservoir and nothing obvious. However, occasionally I smell coolant after I turn off my car.

Today, I actually opened my hood sniffed my engine like a bloodhound and the strongest coolant smell kind of came from the tubes leading into the red circled item. Now of course, it could be coming from somewhere below that spot, but it was in that general area from my unscientific sniff test lol. But it really seemed to be emanating from those two tubes leading into that aluminum piece, but I saw no signs of leakage.

Is losing a few ounces of coolant normal? Thanks.

[flyfishing]

mine leaked and ended up being a leaky turbo coolant line.

[Packy]

My '13 S6 used coolant VERY slowely. last time I took it in for a service they replaced some coolant lines under a TSB. I'd think the 17 would already have it but maybe not. Ask your dealer about it.

[OlyS6]

While you'll definitely have variability in the level within your OEM reservoir, it is not uncommon to have some leak around the rubber gaskets in the coolant lines above the turbos, as well as below the turbos and around the charge-air-cooler.
Given the newness of your car, would definitely take it in to the dealer to have it checked out and have any involved lines and gaskets changed.

[DGVR6]

Having the same issue on my 16

[Frenetic]

Yeah I inspected the coolant lines into the turbos as best as I could and I didn’t see anything (I’ve attached a photo of them in my original post). I’ve seen what leaking lines look like from other threads and I don’t see that in mine.

I looked underneath and also didn’t see any signs of leakage. I spent a lot of time with a flashlight looking for signs of pink crusting everywhere to no avail.

However, based on my very unscientific nose test, the smell seems most prominent in the front part of the engine towards the driver’s side. The past few trips, I would park the car then pop the hood and smell lol. Sometimes I don’t smell anything, other times it’s apparent.

Is our coolant pump and thermostat located in this vicinity? In front of the overflow reservoir?

[cobrario]

Same - dealer can’t find, no visable leaks or drips and doesn’t show on a pressure test. Always slight smell of coolant after driving the car too.

[Frenetic]

Well that’s a relief. I’m not saying misery loves company, but it’s just good to know I wasn’t the only one noticing this.

Our coolant systems are supposed to be fully sealed, meaning any loss would or should indicate a leak. From what I’ve researched, the most common causes are seals around turbo coolant lines, failed or failing thermostats, failed or failing coolant pumps (these are attached to each other), raidiator pin holes, cracked hoses and one report of a water intercooler that was damaged that passed pressure tests but failed under heated loads.

However, considering the temperature often reaches boiling points, in excess of 230 F I would estimate, that maybe it’s just minuscule amounts of steam seeping past O rings. At that temperature, the pressure must be very high.

Considering my loss has been in mere ounces, that might explain it (or could be my own wishful thinking lol).

Anyone else experience mysterious, slight coolant losses and/or the smell of coolant after driving? Is the smell more prominent on the front driver’s side (for US cars)?

[gk1]

What does the level look like in the reservoir when hot? Also at min?

[Frenetic]

Well for me, with outside ambient temperatures in the 40s to 50s, with the coolant set at the top of the bottom arrow for a dead-cold car in the same ambient conditions, I’ve noticed it expand up 12 to 15 mm or about half an inch, after driving around a fully-warmed car.

If you want to measure yours, I would suggest measuring the overfill reservoir first thing in the morning, taking note of the ambient temperature. Take a picture or mark it.

Open the hood a month later and, hopefully under the same conditions, remeasure. Works best if both measurements were done in garage conditions with the same ambient temps.

If you park your car outside and the temp during measure one is a lot higher than measure two, it may show lower simply because of the ambient temp differences, or visa versa.

[DGVR6]

Seems like regardless of the weather, I smell coolant when I open the hood. Almost every week it’s below min. I’ve added about a half a gallon of distilled water in one month. Haven’t had the chance to take it to the dealer yet but I’ll add half a gallon on concentrated g13 and let the run down until the light comes on before I’ll go to the dealer.

No noticeable leaks smh

[AWDYEAH]

I’m glad to see I’m not the only one as well. The dealer replaced a line before I bought the car spilled coolant everywhere. They told me the smell would go away...I’ve been keeping an eye on it and have to add some every few weeks. Still smells...where I had clean up the pink residue from the dealers line change I haven’t seen anymore pink residue.

I also smell it on the drivers side front. The dealer is going to come and get it soon to see what they can find.


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[RedheadNV]

On mine, I lose about 8oz every 1500 miles. I smell coolant every once and awhile, but my HX blew up and was replaced right before I purchased the car. My belly pans still have residual coolant on them, and when hot, I smell it more. I have pressure tested it for over 48 hours and didn’t even lose 1 psi. I’m not sure where it’s going.


2013 S6 Quartz gray metallic

[flyfishing]

Seems like regardless of the weather, I smell coolant when I open the hood. Almost every week it’s below min. I’ve added about a half a gallon of distilled water in one month. Haven’t had the chance to take it to the dealer yet but I’ll add half a gallon on concentrated g13 and let the run down until the light comes on before I’ll go to the dealer.

No noticeable leaks smh

1/2 a gallon a month is a lot. that's a sizeable leak. i'd take it in before it gets worse. mine blew a huge leak out of the blue and had to be towed.

[Frenetic]

I’m glad to see I’m not the only one as well. The dealer replaced a line before I bought the car spilled coolant everywhere. They told me the smell would go away...I’ve been keeping an eye on it and have to add some every few weeks. Still smells...where I had clean up the pink residue from the dealers line change I haven’t seen anymore pink residue.

I also smell it on the drivers side front. The dealer is going to come and get it soon to see what they can find.


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Yeah I’m fairly certain our thermostat/coolant pump is around the front driver’s side based on diagrams I have seen. Not sure if it’s just a coincidence, but the odor really is localized for me as I can’t smell it in the other side of the engine.

[AWDYEAH]

Yeah I’m fairly certain our thermostat/coolant pump is around the front driver’s side based on diagrams I have seen. Not sure if it’s just a coincidence, but the odor really is localized for me as I can’t smell it in the other side of the engine.

Same here, just in that one location.


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[AWDYEAH]

Just found this TSB


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[DGVR6]

Just found this TSB


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Thx I’ll bring this up at service

[14S4GWM]

The coolant dries white and crusty not pink. I’ve had 3 leaks on my s4 and can smell it when I get out of the car in the garage. Drives me crazy.

[cobrario]

Fwiw- mine started after I had a coolant release My last pass at the track, the car did this https://drive.google.com/open?id=0B-...0Fua1FnMGxKYTQ -upon further inspection under the hood, a significant amout of coolant had blown out from somewhere but from where I couldn’t tell- the majority was on the left side (a lot was on the inside of the LF wheel). I drove the car home and no problems, my indy shop and dealer have checked but can’t find anything and I’ve had no issues since other than the smell. That TSB is intersting and I’ll bring it up to my SA- thanks 👍🏻

[Frenetic]

I've been reading the engine self study guide and here is excerpt that shows the cooling system. As you can see, the thermostat and water/coolant pump are located at the front of the engine, driver's side (circled in red). It's funny, but sniffing around the engine bay like a bloodhound really is revealing because the smell is localized, at least to me and my sense of smell lol. The pump and thermostat are attached to each other in one large housing it seems, with the thermostat in a black housing and the pump in a metal one based on the pictures I've seen. I can't see these with just the hood open unfortunately.







Also, I annotated the stainless steel lines into the turbo housing. According to the same self study guide, the RED is coolant outlet, BLACK is the oil line and BLUE is the coolant inlet. So, that housing can leak oil or coolant, or both. It would seem the outlet would be the most susceptible to leaking. Although my housing and lines show no sign of leakage, I know these components are susceptible based on what I've read here and the TSBs that cover these.

[AWDYEAH]

I've been reading the engine self study guide and here is excerpt that shows the cooling system. As you can see, the thermostat and water/coolant pump are located at the front of the engine, driver's side (circled in red). It's funny, but sniffing around the engine bay like a bloodhound really is revealing because the smell is localized, at least to me and my sense of smell lol. The pump and thermostat are attached to each other in one large housing it seems, with the thermostat in a black housing and the pump in a metal one based on the pictures I've seen. I can't see these with just the hood open unfortunately.







Also, I annotated the stainless steel lines into the turbo housing. According to the same self study guide, the RED is coolant outlet, BLACK is the oil line and BLUE is the coolant inlet. So, that housing can leak oil or coolant, or both. It would seem the outlet would be the most susceptible to leaking. Although my housing and lines show no sign of leakage, I know these components are susceptible based on what I've read here and the TSBs that cover these.

Nice find! Where could I find the self study guide? Is it included with the owners manual?


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[Frenetic]

https://www.audiworld.com/forums/att...self-study.pdf

[AWDYEAH]

https://www.audiworld.com/forums/att...self-study.pdf

Awesome, thanks!


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[OlyS6]

Other considerations are the o-rings/gaskets at the bottom of these same metal coolant line returns, and not just the top.

Also, having removed my coolant reservoir completely, it is ineteresting to note that there is an intentional hole at the rear mid-base of the reservoir. I'm assuming it is a pressure blow-off valve- I've also seen coolant leak from this area when the level gets to high or the coolant gets too hot (expanding the volume of the coolant in the system). This may explain some of the coolant smell on the driver's side some of us experience. It is pretty easy to unscrew the 2 torx screws holding the coolant reservoir in place and lifting up on it to look behind it to see if you can see a bunch of dried white coolant behind/underneath it. The hose that it is attached underneath the reservoir has plenty of play for you to be able to lift the reservoir out of its bracket without having to detach the hose.

[AWDYEAH]

Other considerations are the o-rings/gaskets at the bottom of these same metal coolant line returns, and not just the top.

Also, having removed my coolant reservoir completely, it is ineteresting to note that there is an intentional hole at the rear mid-base of the reservoir. I'm assuming it is a pressure blow-off valve- I've also seen coolant leak from this area when the level gets to high or the coolant gets too hot (expanding the volume of the coolant in the system). This may explain some of the coolant smell on the driver's side some of us experience. It is pretty easy to unscrew the 2 torx screws holding the coolant reservoir in place and lifting up on it to look behind it to see if you can see a bunch of dried white coolant behind/underneath it. The hose that it is attached underneath the reservoir has plenty of play for you to be able to lift the reservoir out of its bracket without having to detach the hose.

I’ve had mine out a handful of Times try not to track down my leak. Haven’t seen this, guess I may have to look again.


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[shoe3k]

Other considerations are the o-rings/gaskets at the bottom of these same metal coolant line returns, and not just the top.

Also, having removed my coolant reservoir completely, it is ineteresting to note that there is an intentional hole at the rear mid-base of the reservoir. I'm assuming it is a pressure blow-off valve- I've also seen coolant leak from this area when the level gets to high or the coolant gets too hot (expanding the volume of the coolant in the system). This may explain some of the coolant smell on the driver's side some of us experience. It is pretty easy to unscrew the 2 torx screws holding the coolant reservoir in place and lifting up on it to look behind it to see if you can see a bunch of dried white coolant behind/underneath it. The hose that it is attached underneath the reservoir has plenty of play for you to be able to lift the reservoir out of its bracket without having to detach the hose.

I noticed dried coolant in my s6 after a month of ownership, which was about 500 miles of driving. I wiped it a few times but it never came back, but I will look to see if I have a hole in the rear of the reservoir. Thanks for this.

[Frenetic]

Is this the hole? I googled these images. Is it wide open or is there a flap? Just seems weird as everything I’ve read says our system is sealed.


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[kpriv]

I haven't flipped mine upside down, but that is likely it. If you unscrew your coolant reservoir cap, you can see that it drains from just outside the threaded edge. I don't believe the system vents through this hole other than if you open the cap under pressure. This is to prevent hot coolant from spraying up and out -- instead it drains from the bottom before you can get the cap unscrewed. I became enlightened on this subject when purging the system after installing the ams HX. Dumped a whole lot of coolant onto my garage floor in the process...

[Frenetic]

Hmm, I just noticed our cars don’t have traditional pressure relief radiator caps. This is my first audi, so I’m not use to not seeing that.

[AWDYEAH]

Hmm, I just noticed our cars don’t have traditional pressure relief radiator caps. This is my first audi, so I’m not use to not seeing that.

I’m in the same boat lol. The technology this car uses under the hood is wild.


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[Frenetic]

I figured it out.

Our cap on the reservoir is a solid venting cap with dual chambers. You see the red circle on the lid area, that goes to a separate (DRY) area of the overflow reservoir and to what I assume is that hole on the bottom of our tank. So it DOES PROBABLY VENT THROUGH THAT HOLE I SHOWED IN THE PREVIOUS PICTURE. I looked down that separate hole carefully and there's no coolant in there. So any venting will happen in the overflow reservoir versus a more traditional cap that vents out directly. So the cap is the pressure relief valve so to speak, but it just vents internally into a separate chamber and out the bottom of the reservoir into that hole.

So, maybe all we're smelling is that venting. However, that means our coolant is getting extremely hot and over pressured. I noticed that there was some signs of crusting in that chambered area so it did vent. One thing I noticed is that during short trips where my car barely heats up, I never smell anything, only when it reaches full temperature.

This could be normal or maybe signs that the thermostat is sticking slightly, but it's plausible that this is the leak without any leaking so to speak, but something is causing it to over pressure (or maybe that's just normal, I don't know).

Yes, I'm a geek and curious like crazy, lol.




Here is a picture of our cap that has is also chambered. The arrow points to the hallow area that allows venting into that red circled hole that showed above.

[AWDYEAH]

I’ll take a look at mine as well, I’ve had the cap and reservoir off a few times. I still think my smell is coming from the front of the car. It also seems like my fans are always kicking in after I get home. My commute is only 6 miles one way and rarely do I get a chance to stretch the cars legs on the way home. I may have a deeper rooted issue.


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[Frenetic]

The fans coming on is fairly normal. My did it from day one and it always does it. I can't recall the fans not coming on post shutdown after the car reaches full operating temperatures.

Turbocharging is extremely heat intensive.

However, venting isn't normal or it shouldn't be normal, should it, under normal operating parameters?

[AWDYEAH]

The fans coming on is fairly normal. My did it from day one and it always does it. I can't recall the fans not coming on post shutdown after the car reaches full operating temperatures.

Turbocharging is extremely heat intensive.

However, venting isn't normal or it shouldn't be normal, should it, under normal operating parameters?

I wouldn’t think so. My last few turbo cars have always just had breather tubes on the reservoir tank, none of them were sealed/pressurized like this tank is.


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[Packy]

Just found this TSB


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did they say what it is then?

[AWDYEAH]

did they say what it is then?

I’ve not been to the dealer yet, still keeping an eye on my coolant level. When I go I’ll be bringing this up.


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[brad65ford]

Shit, count me in as well for this issue though I haven't checked its levels I surely smell it. I purchased a used 2016 rs7 low miles and didn't notice the smell till we stopped a a pup for a burger and drink. Thought it was the piece of shit I was parked next to, turns out it was the piece of shit I was driving lol. I joke honestly since I love the car just would like to find out how to stop this smell since it not correct imo.

So we are all experiencing this right! WTF no solution either, great.. Really don't want to bring into the dealer especially if they don't know the fix either.

[wwhan]

NHTSA ID: 10123588
TSB ID: A191340 2033491-
11/16/17
Supersedes technical service bulletin group 19 number 13-36 dated april 15, 2013. customer may report coolant leaking from the engine area. the leak can be traced to the connection of the water pump and the hose leading to the heater core.

NHTSA ID: 10121326
TSB ID: A191345 2034439-
10/30/17
Supersedes technical service bulletin group 19 number 13-43 dated july 12, 2013. the coolant warning light is illuminated. coolant is leaking from the front intercooler radiator because of stone damage to the radiator.

NHTSA ID: 10119815
TSB ID: A191665 2039018-
10/21/17
A small amount of dry or crusted coolant is seen on the coolant pump housing. the coolant level warning is not on. a minor coolant leak is possible during the break-in phase of the coolant seal on the coolant pump.

[brad65ford]

NHTSA ID: 10123588
TSB ID: A191340 2033491-
11/16/17
Supersedes technical service bulletin group 19 number 13-36 dated april 15, 2013. customer may report coolant leaking from the engine area. the leak can be traced to the connection of the water pump and the hose leading to the heater core.

NHTSA ID: 10121326
TSB ID: A191345 2034439-
10/30/17
Supersedes technical service bulletin group 19 number 13-43 dated july 12, 2013. the coolant warning light is illuminated. coolant is leaking from the front intercooler radiator because of stone damage to the radiator.

NHTSA ID: 10119815
TSB ID: A191665 2039018-
10/21/17
A small amount of dry or crusted coolant is seen on the coolant pump housing. the coolant level warning is not on. a minor coolant leak is possible during the break-in phase of the coolant seal on the coolant pump.

Are these TSB's only for s6's or any c7/c7.5 bodys?