Leaky C5 RS6

[cgc154]

16600

Hey everyone,

I'm new this forum and this car, so figured I had to break the ice with a good ole "help something is wrong" thread! For a little background, the car has 102k miles on it, a new transmission at 67k, GIAC tune, other go fast parts, and the timing belt is due in 4k miles. It has been lowered and I'm still getting used to how the stiff suspension and wide wheels/stance feel when driving, so every vibration and bump have me worried.

I just drove the car home from NYC to St. Paul, MN, a trip of 1300 miles and it drove spectacularly. Wonderful at cruising speeds, new tires drove great, and turned a lot of heads on the free way. As I was beginning the trip, however, I noticed a fairly obvious leak near the suspension a-arm (strut? not sure what to call it. I can't really see exactly where the leak is originating from as the car is low enough I can't get my head under) on the front passenger side.

The liquid is clear and watery (and doesn't taste like anything, trust me), not obviously colored or oily, making me think it's not coolant (which is usually green or blue in my experience), shock fluid, power steering fluid, or engine oil. I kept a close eye on the temperature sensors and oil and coolant stayed perfectly happy, steering effort and ability didn't change, and the engine didn't shift or sound unhappy at all.

I've done a bit of research and based on leak location and other symptoms, I'm thinking it could be the coolant return pipe (doubtful as there is no smell or smoke), turbo lines, or the temperature sensor. The rate of loss of fluid is pretty high, so I'm a bit worried. It's so watery and no warnings have come up (both via computer or mechanical/visual), so I'm hoping it might be a loose windshield washer fluid hose or something. It tends to leak more when it's up to temp, so maybe a leaky water pump?

I'm planning on taking it into a shop soon, as I don't have the tools yet to do a lot of work on the car, but just wondering if I should be worried/stop driving it immediately, or if I'm ok for now. I'll report back once the shop diagnoses it.

-Colin

[bethridg]

Condensation? Were you running the A/C? If it has OE G12/G13 coolant it will be pink.

[cgc154]

I run the A/C everytime I'm in the car, around 70 degrees F, so maybe? It would have to be A LOT of condensation though, a fairly sizeable puddle appears under the car and I can see the dripping happen. The liquid is definitely not pink, so that's a relief!

[hahnmgh63]

I vote for A/C condensation dripping from the Evaporator drain.
Don't run it long and hard, that GIAC tune is known to run a little lean under full boost. GIAC does some good tunes for other cars, 1.8t, 2.7t, etc... but their RS6 tune is junk but when you tell them it is lean they just ignore the complaints and blame it on the individual car.

[Bigglezworth]

Condensation from the AC resevoir. Feel around the bottom of the AC lines after you've been out and about and you will feel the moisture. It drips down in the exact location you describe. ALL other fluids aside from the 'water' will have color, taste, and a slippery feeling.

[DHall1]

http://www.rs6.com/showthread.php/31815-FS-2003-Audi-RS6

BuffaloRS6's old car.

[Turbowned]

That sounds like condensation, which happens on every car. Perfectly normal.

[papadoc]

http://www.rs6.com/showthread.php/31815-FS-2003-Audi-RS6

BuffaloRS6's old car.

Congrats on your beast!
cgc154, I thought about that car but the drive from Buffalo to Palo Alto was just a bit too long for me. You should be happy with your purchase. And yes, AC condensation.
And do yourself a favor and pick up a http://www.ross-tech.com/vag-com/. Will save you a lot of angst in the future, as will frequenting this board for information and advice.

[cgc154]

I've run the car with A/C and without a few times in the last week. Without the A/C on, there's no puddle! Seems like you guys know what you're talking about. I'm bringing it in to a shop on Friday so I'll have them confirm just in case.

@papdoc: I'm looking into purchasing that. Data-logging is incredibly useful, both for my own interest and for the sake of making sure the car is operating correctly. I'm glad you didn't buy it haha I'm in love! I drove it back to MN from NY and it drove great the whole way.

[cgc154]

The shop (Metric Auto Works in Woodbury, MN) confirmed that it's the A/C evaporator. They figured the larger puddles were just due to MN being so humid this time of year. Besides needing new front tires and a slightly damaged CV boot, they said the car was in good condition (phew!). It's due for the timing belt in the next 3k miles, as well as the 100k service check up, so I think I'm going to jump the gun and bring it in next week to get it looking like new.

[lswing]

Nice, I made the same mistake with my AC one day, sure I had sprung a leak!

Check the web address in my sig for maintenance tips when doing the TB.

[cgc154]

1662616627

Just over $4k for all of this but the RS6 feels almost like a brand new car. Big thanks to Metric Auto Works! With the suspension adjusted and lubed, fresh front tires to match the rears, and everything else that was gone over with a fine tooth comb, the car feels MUCH smoother and more composed through the wheel and pedals. The ride is a lot less rough, all of the driver inputs are more direct, and it's one of the best feelings in the world to not have a warning light on the dash screen! Glad I got it all done right by a shop but would love to start learning how to rip this thing apart by myself. I've got a lot of experience with motorcycles and my school's FSAE car, so once I get the tools I'll feel confident. Item #1 is the ross-tech VAG-com, #2 is a lift so I can get underneath. Any other suggestions for "must have" tools? Also is there a good service manual out there?

-Colin

[bethridg]

Item #1 is the ross-tech VAG-com, #2 is a lift so I can get underneath. Any other suggestions for "must have" tools? Also is there a good service manual out there?

A lift is a luxury. If you have the means go for it; otherwise a quality jack, a set of stands and a nice level surface works well and is much cheaper. The Bentley manual is probably the best but WAAAY over priced IMO. It covers mostly common sense procedures for anyone who has performed more than just an oil change on a car. I bought mine recently hoping for in-depth coverage of the engine internals (specifically torque specs) but was quickly disappointed. Anything beyond a valve cover gasket change and it's practically worthless. Also it's primarily written for the 2.7/2.8 and 4.2 A6 with the occasional RS6 mention. Search the internet, if needed, adapt what you find to the RS and if you are still stuck post it here.

[Other_Erik]

A lift is a luxury. If you have the means go for it; otherwise a quality jack, a set of stands and a nice level surface works well and is much cheaper. The Bentley manual is probably the best but WAAAY over priced IMO. It covers mostly common sense procedures for anyone who has performed more than just an oil change on a car. I bought mine recently hoping for in-depth coverage of the engine internals (specifically torque specs) but was quickly disappointed. Anything beyond a valve cover gasket change and it's practically worthless. Also it's primarily written for the 2.7/2.8 and 4.2 A6 with the occasional RS6 mention. Search the internet, if needed, adapt what you find to the RS and if you are still stuck post it here.

Seconding on the Bentley manual. Since it covers A6/S6/Allroad/RS6, you generally get:

A6: Long and detailed description, sometimes torque specifications, lots of pictures (every step)
S6: Follow A6 procedure, except steps X, Y, Z, detailed description, no pictures, no torque specs
Allroad: Follow A6 procedure, except steps A, B, C, detailed descriptions, some pictures, no torque specs
RS6 - let me quote directly "Follow A6 procedure, adapt as necessary." (This was for the Alternator replacement)

Adapt. As. Necessary. Thanks Bentley, I hadn't considered that possibility!

Best tool you can have is deep google-fu, search string on google with "site:rs6.com", and "site:rs246.com" in separate searches. If you can't find it on rs6, you may get extremely lucky and find someone talking about their old beater C5 on 246.

O_E