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Used RS6 Engine Oil Analysis | How Healthy Is Your Super Wagon?

In Dads Garage

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🔍 Why Does My Audi RS6 Oil Smell Like Fuel? | Surprising Oil Analysis Results! After chasing down the mystery behind my RS6 C7’s fuel-smelling oil — and replacing everything from injectors to sensors — I finally sent off a sample for professional oil analysis. The results? Not what I expected.
In this video, I break down the full journey:
Symptoms of fuel contamination in engine oil
Common causes in the 4.0 TFSI platform
Parts replaced during troubleshooting
Lab-tested oil analysis results
What it means for long-term engine health

If you own an RS6, RS7, or any Audi with the 4.0 twin-turbo V8, this is a must-watch before your next oil change. Learn what to look out for, how to spot early signs of fuel dilution, and whether it’s time to panic — or just change your driving habits.

00:00 Intro
01:22 Why can oil smell like fuel?
02:30 Getting the RS6 in the air
04:30 Taking the under trays off
07:13 Oil draining bucket (top tip)
08:28 Draining the oil & oil sample
11:25 Oil filter removal
14:20 What oil to use
16:30 Oil replacement
17:44 Oil testing kit
18:52 Results

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Thanks for watching

20 Comments

@bessymoocow 1 year ago

hey i work for audi and lemme tell ya direct injected engines will always smell like fuel mildly a faint fuel smell is 100% normal now if you take the oil cap off and its pure gas pungent smell than yeah you got a problem theres a big difference in smell between normal and fault part

@sarcastixx74 1 year ago

Had the same issues as yourself with my own 720hp C7.5. Bought it in March with only 47k on the clock and it happened within a few days of purchse. My issue was with hot starts, would fire up and immediately die. After 2/3/4 attempts it would eventually come to life. Common issue and I knew it was the HPFP's. When these go, hot (non)starts are the most common symptom you'll find. Easy job to swap them out and when you do if you have a look at the springs surrounding the fuel pump pistons you'll normally find them starting to rust. I noticed that the smell of fuel is nearly the same as it was before the new pumps, it's not excessive at all but always there. My guess is your original pumps were actually fine, but as they go with age (not mileage) then you didn't do any harm and we all know the benefits of preventative maintenance.
As for oil level monitoring, there is actually a dipstick you can fit that will give a proper reading. It is listed as for the C6 4.2V8 engine but part no 079115607C will also fit the C7 4.0T engines as well. Our engines need 8.3L of oil so with the amount you put in and then seeing a few hundred millilitres short in the MMI is bang on. Can find that dipstick on the usual auction sites or amazon, etc. Cheers!

@ARM1886 1 year ago

Man of all trade. Amazing talent

@miroslavborislavov5796 1 year ago

Great video and SPME VALUE INFORMATION !!! Thanks a lot

@X055_s5 1 year ago

With the 4.2 S5's it takes 8.8 litres of oil, the last 800ml is what shows up on the mmi...so you cant really go wrong with it as long as you got the biggest bulk of oil in

@fatblokescanfly 1 year ago

Great video and clarifies for many owners. I do think there is potential that many have jumped onto the hpfp change out method too soon.

@tomaszpiekarz2072 1 year ago

You missed one more reason for fuel smell in the oil with the DIE. Short drives on a cold engine. It will do it.

@Timrud1 1 year ago

Just found your channel, youtube suggested it. Nice garage and interesting video - look forward to more! Was a bit worried the car wouldn't be there when you opened the door after warming it up :D

@robczar7479 1 year ago

The oil didn't shear down at all? That's hard to believe. You would think the turbos would want a 5w40 or higher to absorbed all that heat.

@nanakwame9110 1 year ago

Thanks for this video I have the same problem with my rs6 i changed the crankcase and oil screen,the pressure pump and still smells a lil be of fuel..at least yur video has put my assumptions to rest 😅

@bradraistrick6393 1 year ago

Enjoyed the video mate 👍 do you plan on doing any driving videos? Sounds great 😍

@rogerc2364 1 year ago

Great video. What brand floor do you have? And what are you using for ramps for your scissor lift?

@georgewady-tw9fi 10 months ago

Hi my friend, I also have an RS6 C7. I'm having the problem that Bank 1 and Bank 2 are running too rich. Did you have the same error codes? Is it due to the PCV unit or the high-pressure pumps? Thanks!

@jamest5149 1 year ago

Its worth topping up the oil filter/housing with fresh oil as much as possible, shortens the time the oil pressure is low after start up. There some very detailed testing done on this and it makes a big difference to oil pressure and engine wear.

@Mac_F87 1 year ago (edited)

To be fair 5w 30 is more than adequate if you change the oil frequently in the UK. As you know we don’t have mega hot weather and we have good quality fuel. One reason 5w 40 would be beneficial is if someone wanted to stretch out oil changes for whatever reason. That way when fuel dilution is factored in the lubrication properties are still somewhat maintained compared to using a 5w 30 oil.

An oil analysis at the start wouldn’t give you content though 😉 😂

@epreadetot 1 year ago

@InDadsGarage, what year is your RS6?

@LoopBooost 1 year ago

Why dont you use ravenol and mann filter like us rs6 enthusiasts in Germany

@chrishall4926 1 year ago

Since you changed your pcv valve does your oil cap still suck on a lot ? Mine is really strong and if I take it off the engine cuts out how do you actually know if it’s broke ?

@daveross4091 1 year ago

Hi
Do you fancy doin my strainer/pcv etc 😊

@7YALL 1 year ago

hi
great videos
you really scared me with that pcv😂
after you replace it still doing that vacum air when you try to take the oil cap out or is it normal, i got rs7, is doing a bit but no errors on tester a engine run smoothly..