Leaking Red Fluid?

[jeguzik]

Noticed a small stream of a reddish colored oil like fluid underneath my 2013 S4. Any idea on what this is and any normal culprits?

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[Audi 4 Life]

power steering fluid probably

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[BradleyButton]

Power steering, brake, or transmission fluid. They're all pretty much red.


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[jeguzik]

How to tell?

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[Aiserock]

Coolant is red-ish too.

Try smelling it, that should point you in the right direction.

[quickglx]

Well since you have a 13, it's not ps fluid... you have electric steering. To my knowledge the closest to red fluid you should have is coolant. And it is pink.
OEM brake fluid is clear.
DSG is a greenish golden color.
I believe manual trans and gear oil is all mostly a golden color.

Only red that I can really recall is engine mount fluid or sometimes other suspension mounts... none of these should or really could "stream" out though? Sure that's coming from your car?

[jeguzik]

It is puddling in the front mid behind the radiator biased towards the passenger side

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[Dr GP]

You either have a puncture of the radiator, IC radiator, a hole in a coolant hose or a failing water pump. My best guess is WP or puncture of either of the radiators. Remote chance it could be the T stat.

[RecklessactN]

You either have a puncture of the radiator, IC radiator, a hole in a coolant hose or a failing water pump. My best guess is WP or puncture of either of the radiators. Remote chance it could be the T stat.

Agree with this, I had a puncture in the auxiliary front mount radiator. The fluid was redish and all over the belly cover which annoyed me bc I had to make sure nothing else was leaking.

[jeguzik]

This all sounds very bad. Hoping it is a loose hose or something simple.

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[RecklessactN]

This all sounds very bad. Hoping it is a loose hose or something simple.

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If its one of the auxiliary radiators its not that bad! I changed it out myself using a socket set and some other household tools. You can follow instructions on how to remove it from APR / AWE using their front mount radiator install instructions. Did it in 3ish hours (did it 2 years ago)?

[Dr GP]

Dealers have charged owners as much as $850 to change the IC radiator. I paid $450 in 2011

[jeguzik]

What is an ic radiator or auxiliary radiator? Do we have more than one?

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[Brother Owl]

What is an ic radiator or auxiliary radiator? Do we have more than one?

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B8s have an auxiliary radiator behind the fog grille (driver side?). B8.5s do not

[Dr GP]

B8s have an auxiliary radiator behind the fog grille (driver side?). B8.5s do not

Didn't know that about the B8.5s

[jdcarnes]

It is puddling in the front mid behind the radiator biased towards the passenger side

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I had a similar location, except on the driver side.
My leak ended up being the hard plastic line that ran from head-to-head and connected to thermostat.
The leak wasn't noticeable until I saw a small stream trickling down the block. I thought it was the thermostat/waterpump.
When I tore it down, I took the pipe off and the inside drivers side flange was broke about 1/3 of the way around ($90 parts) from Audi. (Labor probably 3-4 hours since the car has to be put into service position + Coolant = ~$500 depending)

Since it is passenger side, you can rule out the Aux intercooler. B8.5's don't have them and the B8's are on the driver side.

[jeguzik]

Early diagnosis from the dealership is a leaking coolant pump? I am out of warranty now but they will ask Audi USA. If not covered how bad is this job? At 37k miles any other things I should have done at the same time?

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[S4'ed]

Also replace your coolant thermostat.

[jeguzik]

Any reasoning to do this? Are they also known to fail?

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[Dr GP]

Any reasoning to do this? Are they also known to fail?

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They fail more often than the water pump. Save yourself some money and replace it while they have the supercharger off to replace the WP. The parts are a lot less costly than the labor to get the Sc off to replace them. If you have any oil consumption issues (like I do) replace the PCV valve as well. If you don't have an oil consumption issue, leave the PCV valve alone.

[jeguzik]

Thanks for the heads up!

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