[Biturbos4] Boost Leak & Dealer Experience (long)

Quincy Chiang b5quattro at shaw.ca
Thu Mar 17 01:35:42 EST 2005

Hi everyone,

Some of you may remember my post about boost leak and such from last week.  Anyhow I finally brought my car in this past Monday (couldn't get an appointment last week) and here's what happened.  I'll start with a quick background to refresh your memory.


My S4 has been feeling low on power lately, and my boost gauge doesn’t seem to show full boost anymore.  A quick VAG-COM scan (borrowed it from a friend, I need to get me one at some point!) showed a fault code:

17965 – charge pressure control: positive deviation
        P1557 – 35 - 10 --- intermittent

And boost log seemed a little weird too.  After some research on AW and with the help from you guys on this list, we concluded that it’s a boost leak somewhere, and many components maybe at fault, ranging from TBB, BPVs……

My other complaint is a squealing blower motor from the climate control system.  It’s been making this horrible high pitch noise whenever the temperature dips below –20C.  It did that last winter and also this winter.  Unfortunately whenever I get a change to go to the dealer it’s always too warm to make noise.

So I booked an appointment with my friendly dealer on Monday to have it checked out.

Monday morning:

I brought my car to the dealer in the morning, waited there, and here's what they found:

1. MAF not reading right, need replacing
2. left side BPV stuck, will replace
3. crankcase vent tube/valve is leaking, will replace
4. will update TBB and clamps as per TSB

But here's the kicker... after waiting for 1.5 hours, the tech called the service advisor at the front desk, asked her to ask me if I had modified the exhaust system.  I said no, thinking can't you tell by looking at it?  She then went into the shop, chatted with the tech, then she came back out and talked with the service manager behind closed door.  At this point I was thinking something big is up, but I couldn't imagine what it can be.

After all that, she finally spoke with me, saying something about the MAF and a few other things.  I thought no big deal, those suckers are known to fail, even the Hitachi ones on >'01 cars, but the impression I got from them was that it's a HUGE problem.

So I requested to speak with the tech, and he explained what's wrong.  Then he proceed to ask me if my car's chipped, seeing that I have suspension (Stasis Tracksport) and a boost gauge installed.  I said no, the only other mods are the pair of BPVs, which I replaced last summer with the 710N's from the TT225, after I started to hear BOV “psssssshh” noises.  That seems to have raised concern as well, even though he seems to be aware that those are better than the stock 710A's (for half the price!).  He then told me that they could void my entire warranty based on the fact that I have modified suspension (!!!), as any mod on a car is enough to void all warranty.  And that I should be thankful that my service advisor and manager approved my repairs this time.  And if my car still doesn't drive right after this, he'll have to check the ECU for chipping (which I don't have) and investigate further.

I was pissed when I heard that.
1. They implied that I lied to them about my mods, showing very little trust.
2. Voiding all warranty because I have coilovers??  I know for a fact that they can NOT do that, they MUST be able to prove the relationship between the modified parts and the failed components according.
3. I should feel like as if they're doing me a favour?!  What the !@#$

Honestly I feel like they were using scare tactics on me, and I don't like it one bit.  I understand that there're people who lie about their mods to get warranty claims, and I also understand the dealers are under some pressure to crack these things down and are caught between AoA/Audi and their customers.  But I hardly think what I went through today was neccessary.  If they consider this to be a major repair, what're they going to say if my turbos go?

The car won’t be ready for a while so I got a ride home.

Monday afternoon:

The dealer called me at around 3pm that my car’s ready.  I got there and they showed me quite a list of the things they replaced.  Basically a new MAF, the entire crankcase breather system due to cracked joints in several places (a good size mess of black hoses at back of engine), one BPV, as well as a new blower motor, pollen filter and clip.  They didn’t say anything else, just happy to hand be back my keys.  I requested to speak with my tech, and he was glad to show me the failed parts inside the shop.  Here’s what I found:

- The left side BPV (710N) is stuck, there’s oil inside
- A lot of oil inside the MAF, you can see it on the screen.  This is due to the stuck BPV
- Several cracks in the crankcase breather hoses, the entire hose assembly looks quite messy.  Note that this whole thing as been updated as per a TSB, so I got the latest version of this part(s)
- The original TBB isn’t torn yet, I was surprised, but he replaced it and all 3 clamps with updated parts as per TSB, good for him!!
- The old pollen filter was quite dirty, probably caused the blower motor to work extra hard hence making it wear out quicker

My tech was very professional and competent, he explained to me very well on what he did to my car, and I was happy with his work.  In fact I’ve been told by several other local Audi owners that this particular tech is probably one of the best at that dealer.  I figured he said those things to me in the morning as a “standard procedure”, probably just did what he was told.  I certainly felt much better that afternoon than when I left there that morning.

Final thought:

Since I got my repairs, I really shouldn’t bitch about stuff.  And I was very happy that they replaced the blower motor eventhough it wasn't squealing at the time (temperature not cold enough).  But still I didn’t appreciate how they treated me that morning, and the stuff they replaced weren’t really that odd and expensive.  I’ve read from here that many people have had these and many other stranger parts replaced under warranty, no questions asked.

Well I have another 8 months of warranty left, let’s see how it goes the next time I go it.

Just out of interest, here’s the list of stuff they replaced:

Qty  Part #           Part
1    078-133-356-T    TBB (updated)
1    078-133-343      large TBB clamp (updated)
2    078-133-3430A    small TBB clamp (updated)
1    06C-133-471-AX   Air meter (MAF)
1    034-145-710-B    Bypass valve
1    078-103-235-R    Hose
1    078-103-485-E    Cover
1    N-103-100-01     Clip
5    N-100-911-01     Clip
2    N-020-353-5      Hose
4    N-102-334-01     Clip
1    N-102-020-01     Clip

1    8D1-820-021      Fan (blower motor)
1    8A0-819-439-A    Pollen filter
1    8D0-819-145-A    Clamp

I do have 2 questions though:
1. I've never heard of the 710B bapass valve.  They suppposedly superceeded the 710A, anyone know what this about?  Better and still worse than te 710N?

2. Also I noticed a "X" at the end of my MAF part #.  Does this mean it's an remanufactured unit?  If so I may have to bitch about that....

Sorry for ranting, just wanted to share my experience and add some knowledge to the collective.

'01.5 S4 - seems to be in better health
'90 CoupeQ - aging

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