Vacuum boost pump (breather hose) and oil leaks

shatiras · 02-03-2005, 05:35 PM

Here is a real life story in case anyone has doubts about the faulty design of the vacuum boost pump which leads to failure of valve cover and camshaft adjuster seals:
I have a 2.8Q '99 A6 and about a week ago, on my way to work, smoke started coming form under the hood in massive quantities. It was so much that it got sucked into the ventilation system and filled the interior of the car. I stopped the car and with one look under the hood I could tell that it was oil leaking onto the exhaust on the passenger firewall side. I limped back home with the ventilation off and smoking so much it looked as if I was grilling hamburgers under the hood.
Having heard the stories about the vacuum boost pump (part number: 058 133 753 B) I disconnected it and determined that it was completely clogged on the side where the valve cover breather hose connects to it. I could neither blow any air in or out that side.
I reconnected the vacuum lines to it, but left the breather hose that comes from the valve covers disconnected and venting under the hood. The result: The massive oil leak stopped immediately, confirming that the blocked pump was causing back pressure to build up and blowing oil through teh seals.

Unfortunately the story does not have a completely happy ending. Even though the massive oil leak stopped, the damage was done and I had residual leaks from both valve covers and camshaft adjusters. I ended up having the valve cover and cam adjuster seals redone at my indy shop.

Currious fact: in order to release the replacement pump part to me indy shop, the dealer asked for a VIN number because they said there is a recall on these (I am not aware of any recall, but that's what my mecahnic was told).
We also cut up the old pump and found it completely gummed up and clogged. It is a very bad design because the passages are so small that they get blocked easily.
I have now put this part on 12 month 12,000 miles replacement schedule. It is easy to do (now that I replaced the calmps with regular hose clamps) and I rather spend the $30 bucks a year than risk another gasket blowout.
I would strongly suggest that folks test this pump. An easy way to do it is to just disconnect the valve cover breather hose at the pump (must cut off existing clamp and replace with regular hose clamp) and check for vacuum at the pump inlet. If no vacuum is felt, the pump is clogged.

JimR · 02-03-2005, 05:54 PM

Good post.

KL'00-2.7T · 02-03-2005, 06:19 PM

not.bitter · 02-03-2005, 06:29 PM

just think how much he could add about clucthes, tires, even having AoA extend the warranty on transmissions for an extra 12/12

pity

JimR · 02-03-2005, 06:51 PM

I need to do a post of links on this, that puts everything in one post.

JimR · 02-03-2005, 06:52 PM

shatiras · 02-03-2005, 06:56 PM

According to ETKA, the APB engine with the manual transmission does not have a booster pump. The APB engine with automatic transmission has a different pump (part # 078 133 701 L), I am not sure if this one is prone to the same problems.

The AHA, ATQ (2.8) and ART (4.2) all have the same pump (the one that is problematic).

Potomac-Greg · 02-03-2005, 07:26 PM

Cargasm2.7 · 02-03-2005, 08:49 PM

TXurS6 · 02-04-2005, 07:27 AM

ahhh, the days when there was actually a little drama around here.

02-03-2005, 05:35 PM	#1
shatiras New Member Account #: 69334 Join Date: Feb 2004 Posts: 65	Vacuum boost pump (breather hose) and oil leaks Here is a real life story in case anyone has doubts about the faulty design of the vacuum boost pump which leads to failure of valve cover and camshaft adjuster seals: I have a 2.8Q '99 A6 and about a week ago, on my way to work, smoke started coming form under the hood in massive quantities. It was so much that it got sucked into the ventilation system and filled the interior of the car. I stopped the car and with one look under the hood I could tell that it was oil leaking onto the exhaust on the passenger firewall side. I limped back home with the ventilation off and smoking so much it looked as if I was grilling hamburgers under the hood. Having heard the stories about the vacuum boost pump (part number: 058 133 753 B) I disconnected it and determined that it was completely clogged on the side where the valve cover breather hose connects to it. I could neither blow any air in or out that side. I reconnected the vacuum lines to it, but left the breather hose that comes from the valve covers disconnected and venting under the hood. The result: The massive oil leak stopped immediately, confirming that the blocked pump was causing back pressure to build up and blowing oil through teh seals. Unfortunately the story does not have a completely happy ending. Even though the massive oil leak stopped, the damage was done and I had residual leaks from both valve covers and camshaft adjusters. I ended up having the valve cover and cam adjuster seals redone at my indy shop. Currious fact: in order to release the replacement pump part to me indy shop, the dealer asked for a VIN number because they said there is a recall on these (I am not aware of any recall, but that's what my mecahnic was told). We also cut up the old pump and found it completely gummed up and clogged. It is a very bad design because the passages are so small that they get blocked easily. I have now put this part on 12 month 12,000 miles replacement schedule. It is easy to do (now that I replaced the calmps with regular hose clamps) and I rather spend the $30 bucks a year than risk another gasket blowout. I would strongly suggest that folks test this pump. An easy way to do it is to just disconnect the valve cover breather hose at the pump (must cut off existing clamp and replace with regular hose clamp) and check for vacuum at the pump inlet. If no vacuum is felt, the pump is clogged.

02-03-2005, 05:54 PM	#2
JimR Member Account #: 1018 Join Date: Mar 2000 Posts: 46,941	Another one for the vacuum booster folder. Good post. __________________ JimR '07 A3 3.2q Lava Gray '99 A8 4.2q Pearl White '99 A6 Avant 2.8q Silver (My old car, son now drives) '06 Boxster S Guards Red (wife's wheels) Support the troops "Over the years, I have come to understand a critical difference between the world of fear and the world of freedom. In the former, the primary challenge is finding the inner strength to confront evil. In the latter, the primary challenge is finding the moral clarity to see evil."

02-03-2005, 06:19 PM	#3
KL'00-2.7T New Member Account #: 8432 Join Date: Aug 2000 Posts: 171	Is this a problem with the 2.7T engine as well? If so, where is this pump/tube located? TIA

02-03-2005, 06:29 PM	#4
not.bitter New Member Account #: 83840 Join Date: Nov 2004 Posts: 141	too bad the guy who broke that story was driven from AWA6 by overzelous Mods just think how much he could add about clucthes, tires, even having AoA extend the warranty on transmissions for an extra 12/12 pity

02-03-2005, 06:51 PM	#5
JimR Member Account #: 1018 Join Date: Mar 2000 Posts: 46,941	Yes. top of engine, just forward of the firewall. I need to do a post of links on this, that puts everything in one post. __________________ JimR '07 A3 3.2q Lava Gray '99 A8 4.2q Pearl White '99 A6 Avant 2.8q Silver (My old car, son now drives) '06 Boxster S Guards Red (wife's wheels) Support the troops "Over the years, I have come to understand a critical difference between the world of fear and the world of freedom. In the former, the primary challenge is finding the inner strength to confront evil. In the latter, the primary challenge is finding the moral clarity to see evil."

02-03-2005, 06:52 PM	#6
JimR Member Account #: 1018 Join Date: Mar 2000 Posts: 46,941	true dat __________________ JimR '07 A3 3.2q Lava Gray '99 A8 4.2q Pearl White '99 A6 Avant 2.8q Silver (My old car, son now drives) '06 Boxster S Guards Red (wife's wheels) Support the troops "Over the years, I have come to understand a critical difference between the world of fear and the world of freedom. In the former, the primary challenge is finding the inner strength to confront evil. In the latter, the primary challenge is finding the moral clarity to see evil."

02-03-2005, 06:56 PM	#7
shatiras New Member Account #: 69334 Join Date: Feb 2004 Posts: 65	It depends.... According to ETKA, the APB engine with the manual transmission does not have a booster pump. The APB engine with automatic transmission has a different pump (part # 078 133 701 L), I am not sure if this one is prone to the same problems. The AHA, ATQ (2.8) and ART (4.2) all have the same pump (the one that is problematic).

02-03-2005, 07:26 PM	#8
Potomac-Greg AudiWorld Super User Account #: 18626 Join Date: Apr 2001 Posts: 21,866	Maybe if we beg, he'll come back. Imagine a guy being banned for solving problems! __________________ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~ Mine: 2002 Mercedes Benz C32 / ///AMG Family Choo Choo: 2008 MB GL320 CDI Track Ho: 1988 Porschuh 944 Recent History: Audi 2002 TT Roadster History: Audi 2000 A6 2.7T Ancient History: Audi 1991 90Q 20V

02-03-2005, 08:49 PM	#9
Cargasm2.7 Member Account #: 56988 Join Date: Jun 2003 Posts: 7,210	I'd guess he'd be bitter. __________________ __________________________________________________ __________________________________________________ Yukon/Camaro/Corvette "The"

02-04-2005, 07:27 AM	#10
TXurS6 Member Account #: 9795 Join Date: Sep 2000 Posts: 7,277	lol and the guy had a sweet disposition to boot ahhh, the days when there was actually a little drama around here. __________________ Jim formerly FtWorthS4 1997 S6

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