What color is RS6 coolant?

**PixieVC** · January 8th, 2012, 03:09

As the topic says... have some fluid leak of some sort from my front end, but I doubt it's coolant. Has a distinctive sweet smell, which sounds like coolant, but... it felt a bit oily. Color of the fluid on the driveway was off-yellow...

Any ideas?

**MaxRS6** · January 8th, 2012, 03:15

Sounds like coolant. If you (or have someone for you) pull the undershield off- you might be able to spot the source. Hopefully, it is just a easily reached hose that sprung a wee. Sometimes the oil cooler develops a leak and that is a more involved repair. Keep a vigilant watch on the coolant level as you don't want an overheated beast.

The BND coolant is yellow. Maybe the prior owner was on the BND wagon.

It could also be the radiator and you might be able to spot this issue by popping the bonnet.

BTW- You are the first one I've seen with the Roho mod...;0

**hahnmgh63** · January 8th, 2012, 03:18

OEM coolant is pink but someone could have used the green stuff (shouldn't though). Glycol will have a slightly oil feel between your fingers.

**PixieVC** · January 8th, 2012, 03:40

Well... it felt oily. I guess its going in to the mechanic Monday for a looksee. Let's just hope it's one of the easy coolant lines... This reminds me, I bottomed the car out a few days ago on a speed bump. Don't worry, I was going slow... but it made an awful noise as the underside of the car dragged along... hoping that doesn't have anything to do with it...

**hahnmgh63** · January 8th, 2012, 03:57

Should be other things scraped before coolant lines like: lower intercooler hoses, exhaust, front swaybar center links. Hopefully the oil pan isn't one of them as a dent in the bottom can affect transmission operation by fully or partially blocking the fluid pickup between the pan & filter.

**PixieVC** · January 8th, 2012, 04:15

OK. I'm not worried - since then I've put 200 miles on the car, no issues. I also don't have a coolant warning light - and nothing additional appears to have dripped since the stuff was discovered. It might even have been water from the AC compressor... water dripping onto driveway will get oily after its soaked into the concrete a bit. My determination of color came from trying to soak some with a paper towel... and not much came up. It smelled 'sweet', but not overly so... and this is the same spot where I used to park my E55 which would leak a quart of oil every 1,500 miles...

I'll monitor the situation, and be sure to watch for the Low Coolant warning to come on (it hasn't.). Might be a false alarm... I'll know tomorrow, as it's going on a hundred mile trip. Thanks for the replies...

**hahnmgh63** · January 8th, 2012, 04:22

Not to worry you but the Power steering fluid is green in color and would be coming from the front left side most likely if leaking a little from the cooler, pump or a few hoses there. Further back and central if coming from the steering rack but they are not prone to failure.

**SzymekCRX** · January 8th, 2012, 08:17

Dip the cue tip in the leaked fluid. Dip another one in the coolant. Compare

**905084** · January 8th, 2012, 16:47

Put a clean drip pan underneath it. The stock pink coolant is almost impossible to tell color in small quantities. Also, because of the front belly pan it is difficult to tell the leak location because it will leak in one place then run along the belly pan till it gets to a duct opening and drip.

Keep an eye on the level of the coolant in the tank (on the firewall). Don't wait for the low coolant light to come on.

If it is the oil cooler to block pipe like my 2000 4.2 it's a PITA. It's a $20 part but the labor to get to it.....$$$$. Good luck on the drive.

**PixieVC** · January 9th, 2012, 00:14

Definitely a coolant leak. And it's getting much worse. A nice puddle under the car after arriving at my destination. Strong smell as well. Was able to ascertain where it is coming through the drip pan: passenger side near the firewall. Nice and pink... FML.

**MaxRS6** · January 9th, 2012, 00:42

As 905 stated, please keep a close eye on the actual coolant tank level, and don't depend on just the coolant light. Sometimes, the sensors or other items can keep the actual light from going off. You do not want to run the RS6 hot for any length of time or you risk vedy bad things jumpin down from the stars.

Good luck with the repair and hopefully it is relatively minor.

I've certainly bottomed my car a few times and gone through a few undershields- it just happens at times no matter how careful one is. One time, I had to make an evasive maneuver to keep a very large truck from crushing Crazy. I had just put a new undershield on the car a few weeks earlier. Yep- you guessed it- the maneuver while keeping my car in an unadulterated fashion- did knock a couple of holes in my new shield. Therefore; I pop riveted some aluminum pieces in the newly created openings to somewhat protect the lower intercooler hoses.

**hahnmgh63** · January 9th, 2012, 01:31

The passenger side by the firewall could be a number of things. There is a coolant pipe that passes under the right exhaust manifold and meets a hose right at the back. The Turbos have a coolant inlet and outlet pipes. There is a cross engine manifold which goes from the back of each cylinder head to the other cylinder head. There aren't any coolant pipes at the bottom that you would have scraped. Towards the front of the engine on the right side there is the infamous oil cooler coolant pipe (just over 2" long) that is plastic and gets brittle and sometimes cracks with age.

**lswing** · January 9th, 2012, 05:07

I had both of my aux radiators leaking, pulled them off, it was easy to see once on a lift, but there was no visible fluid under the car so it must have been slow.

**905084** · January 9th, 2012, 05:52

Take your time to troubleshoot it right. Start out by dropping belly pan and driving it (not sure this is ok on the RS6 but certainly ok on a regular A6 4.2). Monitor the leak location and you should be able to tell if it is from the oil cooler to block pipe or from the right aux radiator (further outboard). There are a dozen other places it could leak but stick with the known high probability areas. If the coolant is pink, you can buy the Pentafrost at NAPA and add as necessary and continue to drive your beast. Don't forget to dilute it 50/50 if you just add it to the coolant tank.

Aux coolers I would think could have the input and output capped and stowed without removing the intercooler or hoses as they appear to be T'd off of the cooling system but not sure. That would be the easy fix.

The intercooler to block pipe is another story. Bumper comes off, front end to the service position, drain oil and coolant (I reused most of my coolant that I could cause Pentafrost ain't cheap). Drop the right engine mount because the the oil cooler is part of it. Make sure the front engine torsion mount is loose because of you don't, you'll tear it and have to RTV it back together (yep, fun). Pull the 5 bolts from the oil cooler and pull it. Put in the $50 worth of parts (plastic oil cooler pipe, 2 rubber O-rings, oil cooler gasket) and installation is the reverse of removal.

I really hope it's your aux radiator Pixie...or something else cheap and easy!

**SzymekCRX** · January 9th, 2012, 07:10

I'd go for the pressure test. I'd reveal the source of the leak

**hahnmgh63** · January 9th, 2012, 09:20

I second the pressure test to reveal the leak, maybe with the engine partially warm helps too. 905084 description of the oil cooler is a fairly good step by step. One thing is that you need to make sure the (Torx or Allen, can't remember) tool is all the way in the 5 bolts as they are usually tight and prone to stripping. And for less of a parts cost you can do much better by upgrading from the cheap OEM plastic 2" coolant pipe to an Aluminum one that is double O-ringed from Bufkin engineering for less than OEM, I think it is $25. I installed one in my car while I had the engine out as a preventative measure.

**lswing** · January 9th, 2012, 16:25

Originally Posted by hahnmgh63

I second the pressure test to reveal the leak, maybe with the engine partially warm helps too. 905084 description of the oil cooler is a fairly good step by step. One thing is that you need to make sure the (Torx or Allen, can't remember) tool is all the way in the 5 bolts as they are usually tight and prone to stripping. And for less of a parts cost you can do much better by upgrading from the cheap OEM plastic 2" coolant pipe to an Aluminum one that is double O-ringed from Bufkin engineering for less than OEM, I think it is $25. I installed one in my car while I had the engine out as a preventative measure.

Just contacted James since I'll have the engine out next month, thanks, hope he still makes them!

**MaxRS6** · January 9th, 2012, 16:29

^ I received one from James about 2 months ago. He was very responsive and sent it out same day as I contacted him.

By the way- "The Girls" are boxing up the package for Scroll this morning. Will have a track# for you later today.

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