Where does the power steering fluid go?

[jbourne]

I feel like by the time I am fully settled into this car, I will have addressed almost every single problem point that it's famous for. Lol.

So I think my steering fluid is going somewhere. I'm not sure if the previous owner just let it get so low that it was almost dry - I've been topping it up for a few weeks now and it seems to dissipate "somewhere". I don't know if the whole system is so empty that it's just rebalancing/sucking in any fluid I give it, or if it's just leaking out somewhere. There's an occasional moan when the steering is at full lock, though it's gotten much better (i.e. much less frequent) once I noticed that it was almost dry. When I add liquid, it will go to "max" on the dipstick, but after driving around a while, it will hang closer to "min", but more or less stay there. When I first noticed the absence of fluid, it was so low the dipstick wasn't even registering. I added about a half quart since that time.

So my questions are:

1. How do I diagnose whether it's really leaking or not? There's nothing on the garage floor. Would this show on the brake calipers? If I clean them perfectly, would any drizzle get on them?
2. If not, can I see it by lifting the car up somewhere? I looked underneath the car a few weeks ago and I don't _think_ I saw any obvious leaks, but I may not know where to look properly.
3. If I do find a leak: does the steering rack need to be replaced, and does the engine need to be dropped, or is this something more benign, some seals somewhere?
4. I was thinking of just emptying the liquid and refilling it with a fresh 2qts, but not knowing if it's truly leaking or not, I don't want to waste any fluid. Or should I just do it?

[Jim Haseltine]

When the fluid is low the rack will make noise. If the pump is dry it makes a hell of a lot of noise. Filling & bleeding as long as the rack hasn't been replaced: Fill reservoir to max, wait 30 seconds then top up to max if required. Run engine for 2 seconds maximum. Wait 30 seconds. Check and top up fluid level if required. Repeat until fluid level remains constant. Do not turn the steering wheel at any point.
If an Audi rack is leaking, it usually leaks into the rubber boots at the end of the rack and as on a C6 the rack is in a sort of box section part of the bulkhead it's difficult to check.
However, a common leak point is where the hydraulic hoses fit to the oil cooler and it's usually the one which runs tight behind the left side the bumper. A leak here isn't easy to see, it took me quite a while to work out what mine was leaking, at first I thought it was washer fluid mixing with other stuff, being a strange oily/soapy green/blue fluid by the time it was draining off the under panel. My bumper is off at the moment, I'll post a pic of the offending hose joint tomorrow.

[jbourne]

Got it, thanks. Appreciate any photos. What confuses me is this: I put some extra yesterday evening again, and this morning it's back around the "MIN" mark, and the car hasn't really moved since. But it stays around the "MIN" mark, I don't think it significantly goes anywhere beyond that...

When it leaks out the boot, does it spray over calipers or anything? Like it can't just disappear... or does it spray over the underbody somewhere?

Also: why do you say top up while engine is stopped? I'm pretty sure I've topped up a few times while the engine was running - bad idea?

[Jim Haseltine]

None too certain where the fluid would drain from the rack area but I'd think it'd be somewhere approximately in line with the back of the engine and either towards the centre of the car or the inner wings.
The engine stopped stuff is from ElsaWin servicing directions. I think their concern is trying to avoid the pump sucking in air when the system has been drained.

[Jim Haseltine]

Chatting to one of the RS technicians at the local dealer "Yes, they pretty much all leak there eventually. The hose under the clip shrinks and lets the oil seep past it. Cut the clip off and fit a new one in a slightly different place, there's loads of room for it."

[jbourne]

Interesting. So you're saying it's possibly not the rack itself? Can you take a wider shot? I think this is looking at the car from the front, and towards the left side, right?

In other words, that means I should be able to also visually identify a leak there, right? (if present)

Trying to picture where this is so I can stick the car on a lift and figure this out. Also, which clip? the foreground clip is the coolant pipes, isn't it? Or am I confused?

[edit] is it somewhere on this diagram? http://www.oemepc.com/audi/part_single/ ... 035/lang/e

[Jim Haseltine]

That's the front left taken looking back at the car from the front. From underneath with the lower panel off you can just about see it. The two black metal pipes are for the hydraulic oil cooler (9 on the diagram) and it's the crimped clip (bottom centre 21 on the diagram) on the front hose that leaks.
If you were losing a lot of oil from there it'd be pretty obvious though, at speed most would end up on the front left wheel - mine was only a minor leak but there were spots of oil in the brake duct that side.

[jbourne]

Cool. Going to a place that has a lift midweek, going to jack it up see how much I can see underneath without disassembling half of the car. So this is somewhere around the left wheel well area, right? Does the wheel + wheel liner have to come off to see it or will removing the undertray be enough? (Car is far from me so I'm trying to picture it in my head right now, so apologies if I should be getting it but am not)

[Jim Haseltine]

Just the undertray. The clip is just in front of the left intercooler, with the hose running pretty tight to the inside of the bumper.

[jbourne]

Found it but no leaks there. Hrm. Spent about a half hour with a light going from underneath and from above, can’t find any traces of fresh liquid anywhere. So where the hell is it going?! ...

[jbourne]

Is it in any way possible that the PS fluid ends up on the caliper?

My left yellow caliper is significantly dirtier than the right. Is it possible something is leaking through vents and is ending up on the caliper? Or is the road just dirtier on the left and I'm chasing a red herring?

[Jim Haseltine]

Well, sort of, but then I'd expect there to be evidence on your under tray which from the picture in your oil leak thread there isn't.

[cammmy]

If your car is RHD then I've been told LH side of the car will suffer more quickly. Explanation being that you will have more water/mud/grit being sprayed up into the arches from puddles.

[jbourne]

Well, sort of, but then I'd expect there to be evidence on your under tray which from the picture in your oil leak thread there isn't.

Correct, there's not. So I have no idea where the PS fluid is going, unless as I wrote above, the system was so empty that it's still consuming it to just fill up to the original level. I'm about a half quart in so far (though with this logic, where did it go in the first place?...) Guess I'll monitor it for a few more weeks, but it HAS to come out of somewhere eventually, no? I mean it's not like the car converts it into horsepower or anything.

If your car is RHD then I've been told LH side of the car will suffer more quickly. Explanation being that you will have more water/mud/grit being sprayed up into the arches from puddles.

Ahh... humm, that could entirely be the case, I've completely not considered that. I like benign explanations for possibly terrifying problems. Thanks.

[c3nturi0n]

You could argue that it is a bad design... but as everything else, nothing is made for life (at least not these days).

I had mine replaced recently as it was 'dripping' occasionally. Not that i can feel anything better steering wise but i'm glad it is done / dysted.

FYI... front bumper and passenger side headlight had to come off.