2013 S6 - Gear oil smell inside the car after warmed up

[97B518TQM]

As the title states, lately I can smell gear oil inside the car after the car has warmed up and I am sitting at a stop light. When the car is moving I can't smell anything, it's only when it's sitting in one place and running.
I took a good luck under the car for any leaks. I couldn't find anything. I thought it might be an engine mount leaking, assuming the fluid from one would have a similar smell, but they are both dry. I am a bit confused. I replaced the dsg fluid 5k miles ago with LiquiMoli fluid. Again, everything looks dry under there, yet the smell is very noticeable and strong. I always have to turn the air re-circulation on to prevent the smell from getting inside the car when sitting at a stop light.
Another interesting thing is, when I open the hood when the car is hot and try to smell it in the engine bay I can't smell anything remotely close to gear oil smell. I am really confused. Has anyone dealt with something like this at some point?

[gk1]

FWIW motor mount fluid does not smell like gear oil.
Is there anywhere it could be dripping onto the exhaust, so then you would not see it on the ground necessarily, but would certainly smell it.

[Cris_OO7]

I had the same scenario you described. For me it was the turbo oil line seals leaking very small amount. Check the top of the turbos.


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[s4majid]

I have the same issue. I have been looking for a year for the source. I even paid a local shop to try to find it and they could not. With mine, you can't smell it in the summer when using the AC. But in the fall and winter when using the heater it's pretty bad.

I had the same scenario you described. For me it was the turbo oil line seals leaking very small amount. Check the top of the turbos.

I have replaced my oil line o-rings even though there wasn't any evidence they were leaking and it didn't solve it for me. Also, if this was the case popping the hood, you should be able to smell it. In my case, it's the same as the OP.

This is just a crazy thought. I know I need a new clutch. If the current one is slipping to the point where it is "burning" would you be able to smell it outside the transmission? I think it's a wet clutch so I have no idea if that's even possible. I guess I'm just hoping the two are related so that when I replace the cutch both problems are solved lol.

[Cris_OO7]

I have replaced my oil line o-rings even though there wasn't any evidence they were leaking and it didn't solve it for me. Also, if this was the case popping the hood, you should be able to smell it. In my case, it's the same as the OP.

In mine it would only leak under load. So when I would check at idle or engine off you couldn’t smell anything. But u can see the oil discoloration around the turbos lines


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[gk1]

I had the same scenario you described. For me it was the turbo oil line seals leaking very small amount. Check the top of the turbos.


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Interesting. My turbo oil line seals started to seep a bit and I replaced them as well. Never noticed any smell. Also I've never felt motor oil smelled the same as gear oil.
Out of curiosity what oil where you using?

[slowguy]

found this thread after a quick search. I am guessing the turbo lines as well. I have the exact same issue and it's terrible. I also changed the orings on the turbos (twice now). Terrible design imo. rubber orings on an exhaust component (even if it has fluid flowing through it). I too don't see any evidence of oil coming out and the OP is correct in saying it smells like gear oil or to me even similar to natural gas, but I'm guessing that's because it goes through the carbon cabin filter. I changed the passenger side orings again last weekend thinking it would resolve as I could see the oil crust on that turbo. The driver side, however, is completely dry and no evidence of leaking - hence the reason I searched for "oil smell" on the turbo wondering if there might be another common location oil could get on hot exhaust components. I don't think I've ever owned an Audi that didn't smell like burning oil at some point or another. It used to be the valve cover gaskets on every 2.7t and 4.2t I owned in the past.

[97B518TQM]

I will check around the turbos. These turbos are brand new SRM RS7 cores with about 5k miles and now and when I installed them I definitely put brand new orings. If they fail that fast.... well it is an audi so it wouldn’t be shocking. Every turbocharged Audi I have owned has had oil leaks from the turbo lines. The 2.7t was the worst, until I replaced the turbos with some Tial 770s with completely different oil fittings.


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[Dasquade]

Maybe it is the fact i have my manifolds/hot side turbo/dp heatshielded and insulated (armor heat shield) but i'm burning though coolant o rings like crazy :(. Oil o rings are fine, always the coolant o rings and driversside turbo. Swapped one 2.5K kilometers, been good but hadn't pushed it a lot. Recently pushed it a few times good and...leaking again. Think i will try to find a slightly bigger o ring and see if it seals better. Normally the ones i have should be good and needs a fair amount of pressure to pop the lines in with o ring....Indeed an other very poor designed item (or something is wrong on mine).
Also never understood why they had the turbo cooling last in line and shared with the engine cooling....i know in ideal world everything would have it's own divorced cooling system, some need the heat to warmup the car...

[97B518TQM]

Turbos are dry and still like new. I think I found the source... IMG_6088.JPG


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[s4majid]

Turbos are dry and still like new. I think I found the source...

I've looked in that area numerous times and didn't notice anything leaking there. I'll look again tonight. I'll be installing rear 02 sensors anyways. Hopefully, this is it!

[slowguy]

Where is that? I can make out the converter. I'll look as well tomorrow. Sure will be nice to isolate and fix. edit: I see now, it's peaking down by the firewall between the downpipes. Trans leak or vent?

[kpriv]

Where is that? I can make out the converter. I'll look as well tomorrow. Sure will be nice to isolate and fix. edit: I see now, it's peaking down by the firewall between the downpipes. Trans leak or vent?

It’s a vent. And the venting is referenced in the factory manual. I was wondering if it was a potential issue when I changed my downpipes. Checked with a couple other forum members who had the same thing and verified it as normal. Shouldn’t be actively leaking or wet, but some residue from old venting is normal from everything I found.



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[slowguy]

I thought the same thing- plus, where it's at, wouldn't be leaking down onto anything that might cause it to burn off and thereby get sucked into the fresh air stream for the cabin?

[97B518TQM]

It doesn’t seem like it’s actively leaking anything from there but it’s wet around it and I’m assuming when the fluid warms up the fumes coming out of there just go into the cabin. Perhaps the new fluid (5k miles or so) develops a stronger smell after some time...? I know fluids like redline, for example, have an extremely strong smell even brand new.


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[kpriv]

If you have new fluid, they probably overfilled it. It needs to vent until it gets to the right level then you won’t smell it any more. That’s be my guess at least


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[slowguy]

Checked the turbo seals again tonight. Can’t find any signs of leaking and yes, the smell does seem like the smell of gear oil. I could put the car on the lift, get it to temp with vcds, and check the fill port on the side of the trans. I too just did a drain, fill and filter change. Although, I couldn’t really see down to the vent. It is packed in there with cats and dp’s?

[s4majid]

I cannot see the vent because of the OE downpipes. I'll be dropping the gearbox soon to do the clutch. I'll obviously be able to get a better look then.

[97B518TQM]

If you have new fluid, they probably overfilled it. It needs to vent until it gets to the right level then you won’t smell it any more. That’s be my guess at least


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I did that service myself. You can't overfill the trans as you just fill until it overflows from the fill hole. As long as the car is leveled you can't overfill.

[s4majid]

I did that service myself. You can't overfill the trans as you just fill until it overflows from the fill hole. As long as the car is leveled you can't overfill.

I did the service myself too. The smell was there before and after. And you are correct. It'd be pretty hard to overfill.

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[gk1]

I did that service myself. You can't overfill the trans as you just fill until it overflows from the fill hole. As long as the car is leveled you can't overfill.

The DSG fluid or the center diff gear oil?
For the center diff I'd agree, it is similar to the rear diff, basically fill it til it overflows.
However, the DSG fluid I thought had to be "run through" the gears and at a specific temperature something like this:
"Start engine, drive, and shift through all gears to distribute the transmission fluid; keep driving until the transmission fluid is up to operating temperature (38 degrees C) "

[97B518TQM]

The dsg fluid. Yes, you fill it first, then you get it up to operating temperature as you also run through the gears. Then shut off and and you top it off up to the fill hole level.


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[slowguy]

I did the dsg fill procedure just as described and at the correct temp but my lift doesn’t always lift perfectly level. I just with I knew the exact cause then I’d figure out the fix. Just don’t know exactly what it is that’s causing the smell. Super annoying

[slowguy]

Im wondering now if it's related to the dsg fluid change. I saw a very small bit of oil near the exterior oil filter canister before I put the bottom cover on but I assumed it was related to the fluid that came out when i unscrewed it. I'll pull the bottom cover off tomorrow and take another look. It's been at least a month since I changed it. Next, if it is leaking, wondering what could it be near to burn and smoke.

[gk1]

Also I don't know if this has any bearing on anything but when you did the dsg fluid change did you also do the external filter?
Because there is this warning in the service manual:
Danger of causing damage to the transmission.
The new ATF filter must not come in contact with water. Even the smallest amount of water, such as a drip of water from the engine compartment or moisture from hands will cause the surface of the ATF filter to swell up. Small paper particles from the filter can come loose and contaminate the Mechatronic.

I know they are referencing mechanical damage, but I wasn't sure if the filter swells maybe it causes an issue where fluid vents out?

[slowguy]

I did do both the internal and external filters. I have the factory manual but surprisingly did not see this. As far as I know I didn't get any moisture on the filter.

[slowguy]

Just an update to this. I now have all new turbos, seals, o rings, arp downpipes. After all this work I still never saw any place where it appeared oil was dripping or masking contact with a hotspot. I’m almost positive now that the trans is venting at certain points while driving or at a stop and that smell is being pulling right into the cabin. Now I just have to figure out a solution. I won’t live with it like this. I may start by doing the check procedure again by pulling the fill port while warm and let some run out if it’s too full. Otherside, I’m going to have to rig something up to relocate the point where that thing vents.

[digdah]

I'm in a '13 as well and have the same exact experience. I don't get the smell when the AC is running and cooling the car but when it is cold and it is trying to warm the car the smell is horrible. Funny thing is there is no smell unless are stopped and the car is warmed up. While moving the car smells as it should.

Subbed.

[Mavfan1]

What does it smell like exactly? When I drive my card spiritedly and get to where I am going, my trunk smells like sulphur. I’ve only smelled it in the car once or twice. I am stripped the trunk down and there isn’t any moisture or mold or anything that would make it smell like that. At this point, my assumption is a minor crack in the exhaust pre-cat?


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[slowguy]

The smell is similar to a natural gas smell. I actually went out tonight, pulled the vent cap, attached a hose with a hose clamp and routed just under the car. What do you know? The smell is almost completely gone. Probably shouldn’t say it too quickly as I might jinx myself but I think that was it. I also need to check the dsg fluid level when I get it back on the lift because there must be a reason it’s venting so strongly. My guess is it’s slightly overfilled. We’ll see

As for the sulphur smell you speak of, it’s your catalytic converters. Someone the exhaust made its way into the cabin momentarily

[s4majid]

I finally did my clutch. After getting the gearbox out of the car I still didn't see anywhere obviously leaking.

Honestly, I think what I was smelling was the clutch burning coming through that vent. Since I've done the clutch and solenoids, the car drives great and I haven't noticed the smell anymore. Or I've just been smelling it for so long I'm used to it.

[digdah]

Mine only seems to happen when the heat is running. When the car AC is cooling the car and I am stopped. If it was the clutch wouldn't it be all the time?

I finally did my clutch. After getting the gearbox out of the car I still didn't see anywhere obviously leaking.

Honestly, I think what I was smelling was the clutch burning coming through that vent. Since I've done the clutch and solenoids, the car drives great and I haven't noticed the smell anymore. Or I've just been smelling it for so long I'm used to it.

[hanyoung]

Hopefully I can return some of the good Audi karma that Audizine helpers have thrown my way! As for the $ that inevitably has also been spent.. well...

I had this same issue - 2013 Audi S6. I took it to the dealership twice, all free due to extended warranty (thank goodness).

First time - they found codes P227000 and P227200 and so replaced both O2 sensors. Smell went away for a week but then returned. But car drove much better.

Second time - found high pressure fuel pump leaking from union. No codes. Replaced high pressure fuel pump. So far (two months out), no more smell.

Hope this helps!! My kids were getting sick in the car, so had to get this fixed!

Catalytic converters were also mentioned, I think plan was to replace if the smell came back 3rd time.

[digdah]

Was your smell more like gas? Mine does not smell like gas at all. It is more like burning oil for mine and does not enter the cabin when moving or when the AC is is going..only heat.

Hopefully I can return some of the good Audi karma that Audizine helpers have thrown my way! As for the $ that inevitably has also been spent.. well...

I had this same issue - 2013 Audi S6. I took it to the dealership twice, all free due to extended warranty (thank goodness).

First time - they found codes P227000 and P227200 and so replaced both O2 sensors. Smell went away for a week but then returned. But car drove much better.

Second time - found high pressure fuel pump leaking from union. No codes. Replaced high pressure fuel pump. So far (two months out), no more smell.

Hope this helps!! My kids were getting sick in the car, so had to get this fixed!

Catalytic converters were also mentioned, I think plan was to replace if the smell came back 3rd time.

[Mavfan1]

The smell is similar to a natural gas smell. I actually went out tonight, pulled the vent cap, attached a hose with a hose clamp and routed just under the car. What do you know? The smell is almost completely gone. Probably shouldn’t say it too quickly as I might jinx myself but I think that was it. I also need to check the dsg fluid level when I get it back on the lift because there must be a reason it’s venting so strongly. My guess is it’s slightly overfilled. We’ll see

As for the sulphur smell you speak of, it’s your catalytic converters. Someone the exhaust made its way into the cabin momentarily

That’s cool. Appreciate the feed back


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[hanyoung]

digdah - mine definitely smelled like gasoline. It only happened at stoplights - recirc helped a little bit.

[digdah]

@s4majid - Can you confirm after your clutch replacement you no longer smell it? As far as I can tell in this thread this has not been resolved. It is a pain point for me and I'd love to get it resolved ASAP cause it just ruins the whole experience in the car to smell oil when stopped. If it was your clutch was there other telltale signs or errors indicating your clutch was going? I have no issues right now that I can tell and it really doesn't smell like a burning clutch to me. I really want to resolve this.

[s4majid]

It's tough to say for sure due to the fact that it was specifically when the heat was on. Since replacing the clutch it's been mostly warm.

I have recently taken care of a few other issues that made me think that the clutch burning may not be it. Because of the very distinct smell, I was thinking it had to be coming from the tranny. But I am thinking that it may be more of coolant and oil mixed smell that I'm getting. My belly pans were covered in oil when I bought the car. Wherever the leak was had been fixed. It's impossible to get all of the oil out of these covers. I then had a small coolant leak. Once it hit the belly pan it's not mixed with oil and smells pretty bad. Maybe the issue with it being only when the heat is on is due to lack of air circulation? As in, if the A/C is on, there is a fan on. Right? But with the heat on there wouldn't necessarily be a fan on and no circulation to dissipate the smell. This is all just a guess. Unfortunately, I don't have any solid answers for you.

[digdah]

Cool. Mine also come into the cabin now with the AC going primarily after spirited driving but when heating it was almost all the time at a stoplight. I will be taking the car in for the 75k service soon so I will have them poke around to see if they can figure out what is going on. If they can't find it I will have my Indy deep dive into it. It is driving me nuts.

[digdah]

Just following up on this. Not sure if it was just some oil that needed to burn up but I no longer have the smell on my cabin. I will wait for it to cool down before saying it's completely gone though which in TX is a ways out lol.