SKU: 69785357549

034Motorsport PCV Breather Hose Upgrade - Audi B9 S4/S5/SQ5 3.0TFSI - 034-101-3108

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034Motorsport PCV Breather Hose Upgrade - Audi B9 S4/S5/SQ5 3.0TFSI - 034-101-3108034 Motorsport PCV Breather Hose Upgrade Audi B9 S4 S5 SQ5 3. 0TFSI 034 101 3108. CURRENTLY ON BACK ORDER AT 034 MOTORSPORT WITH NO ETA Upgrade your failure prone PCV breather hose with the high performance, reliable 034Motorsport PCV Breather Hose, engineered for enhanced durability and long lasting performance. The 034Motorsport PCV Breather Hose isn't just an upgrade for tuned vehicles it's also a critical safety enhancement for all EA839 equipped

034 Motorsport - PCV Breather Hose Upgrade - Audi B9 S4/S5/SQ5 3.0TFSI - 034-101-3108.

CURRENTLY ON BACK ORDER AT 034 MOTORSPORT WITH NO ETA

Upgrade your failure-prone PCV breather hose with the high-performance, reliable 034Motorsport PCV Breather Hose, engineered for enhanced durability and long-lasting performance. The 034Motorsport PCV Breather Hose isn't just an upgrade for tuned vehicles - it's also a critical safety enhancement for all EA839-equipped vehicles.

The PCV breather hose on the EA839 relies on a pair of internal check valves to switch between ventilation pathways and prevent the loss of crankcase vacuum or entrance of boost pressure to the engine crankcase; however, these factory components are prone to premature failure. Once these check valves fail, they can no longer regulate crankcase pressure properly, causing the crankcase to pressurize and potentially allowing hot oil to escape that can lead to serious engine damage, including the risk of fire. This failure occurred to a development vehicle in Ashes to Asphalt, documenting the absolute worst case scenario of when the PCV system can fail. This failure can occur on bone-stock vehicles or vehicles tuned with Stage 1, 2, or 3 power levels. The 034Motorsport PCV Breather Hose is designed to offer reliable crankcase ventilation for the EA839 V6 at all power levels.

The 034Motorsport PCV Breather Hose fixes these critical safety issues, allowing the PCV system to operate flawlessly at all power levels for years to come.

Upgrade your factory corrugated plastic, failure-prone PCV breather hose with the high-performance, reliable 034Motorsport PCV Breather Hose, engineered for enhanced durability and long-lasting performance.

The PCV, or Positive Crankcase Ventilation system, on the EA839 is located on bank 2 of the engine (The right side of the engine). It is designed to ventilate the engine's positive crankcase pressure through the breather hose into the intake tract or charge air system. The breather hose plays an integral role in this ventilation system, which uses two check valves to control the flow of crankcase pressure.

How Does the PCV System Operate?

The Positive Crankcase Ventilation System on the EA839 works to remove excess pressure from the crankcase system and relies on the vacuum from the engine's intake system to operate properly. At idle or cruising while not in boost, the engine's charge air system operates under vacuum, drawing air in continuously. During this state, the PCV system utilizes this vacuum to release crankcase pressure into the charge air system through the connection just after the throttle body.

However, when the vehicle is under boost (during acceleration), this connection becomes pressurized, meaning it can no longer provide a vacuum source for crankcase ventilation. When this happens, a check valve in the breather hose closes off this connection, preventing boost pressure from entering the crankcase. At this point, the breather hose is able to draw vacuum from the turbo inlet connection, as this creates vacuum through a siphoning effect as the turbocharger draws air in through the intake.

Whether you are sitting at a stoplight or romping on a backroad, a properly operating PCV system is crucial for maintaining the engine's performance and preventing harmful pressure buildup.

Why is the OE PCV System Insufficient?

The check valves within the factory breather hose are an integral component of ensuring correct operation. However, since these check valves deal with the high temperatures of an engine bay and the transition between vacuum and boost pressure, they are susceptible to premature failure. When they fail, excess pressure can enter the crankcase, causing it to operate under conditions it was not designed for. In fact it's likely these are the same as what Audi uses on naturally aspirated engines, which makes them not up to the task of dealing with pressures associated with turbocharged engines.

As the crankcase of the engine is not designed to operate under pressure, it typically will find the path of least resistance to release this excess pressure. The seals and components inside your engine, which are designed to operate under vacuum, aren't built to handle this excess pressure. In some cases, the path of least resistance is unfortunately the oil cap, which can loosen and expel hot oil into the engine bay, potentially causing a fire.

Audi issued a TSB (Technical Service Bulletin) concerning this failure of the PCV Breather Hose as of 2020, though in our testing 034Motorsport has concluded that even the newest variant of breather hose is susceptible to failure.

Some other solutions on the market neglect the importance of maintaining adequate vacuum pressure from the charge air system and intake tract to ensure proper operation of the PCV system. Because the PCV system relies on these two separate vacuum sources under normal operation, removing one would prevent the crankcase ventilation system from functioning properly.

When these solutions remove the intake tract as a vacuum source, it disrupts the PCV system's ability to vent crankcase pressure at idle or in a cruising state while not in boost. Because the crankcase no longer has sufficient vacuum pressure, seals that are designed to operate with this vacuum pressure can fail prematurely. This lack of vacuum pressure can also lead to the potential of pressurization of the crankcase system and engine damage.

Additionally, many aftermarket solutions have check valves that do not provide sufficient flow to accommodate the boost levels of Stage 3 equipped vehicles. These check valves are too small and this inefficiency can cause restrictions, resulting in reduced flow from the crankcase, causing crankcase pressure to build up.

During the development of the 034Motorsport Stage 3 Dynamic+ tuning suite, the development B9 Audi S4 experienced an unfortunate OEM PCV breather hose failure.

This failure caused oil to be expelled through the oil cap and onto the hot turbocharger, immediately causing an engine oil fire. This failure was documented in our video Ashes to Asphalt, documenting the extent of the damage and how 034Motorsport was able to make the most out of the situation.

Because of this failure, it made engineering a proper solution that was able to withstand the harsh engine bay temperatures and elevated boost levels of utmost priority for 034Motorsport Engineers.

What is The Fix?

034Motorsport began by benchmarking the factory PCV system for flow capacity and other check valves on the market. Due to this, we opted to engineer and develop our own proprietary check valves that offer fantastic restrictionless-flow capability when open, and create a strong seal when closed, capable of holding over 40+ PSI of pressure and dealing with the high temperatures this system is subject to. These check valves utilize a durable synthetic rubber diaphragm that offers superior high heat and chemical resistance.

034Motorsport engineers designed the 034Motorsport PCV Hose to be used with the OEM Factory Air Oil Separator, as we found during testing that this unit provides excellent crankcase pressure control and is capable of supporting the flow needed at Stock through Stage 3 power levels without failure.

The 034Motorsport Check Valves are housed in a high-flow 4-ply reinforced silicone hose, specially designed to not collapse or inflate under vacuum or boost pressure. These silicone hoses are molded to allow for the factory engine cover to be utilized with the 034Motorsport PCV Breather System installed.

The 034Motorsport PCV Breather Hose uses OE-style multi-use connections, which allow for easy installation and removal when servicing your turbo inlet.

The OEM breather hose includes a new turbo inlet system as well, increasing the cost of this failure-prone component. whereas with the 034Motorsport PCV Breather System installed, there is no need for excessively costly OEM replacement components, as the 034Motorsport Breather Hose is engineered to last the lifetime of your vehicle.

The result is the 034Motorsport PCV Breather Hose, which isn't just an upgrade for performance enthusiasts€”it's a critical safety enhancement for all EA839-equipped vehicles. It has been extensively tested on several 034Motorsport development vehicles for upwards of 2 years at varying power levels to ensure its performance and reliability, whereas the OEM breather hose can fail in as little as 3 months! The 034Motorsport PCV Breather Hose is suitable for all vehicles including those that are bone stock or upgraded with Dynamic+ Stage 1, 2, or 3 tuning!

Features:

  • Direct Replacement of the Failure Prone OE PCV Hose
  • Ensures High Flow Crankcase Ventilation to Prevent Crankcase Pressurization
  • Eliminates Potential Boost Leak at OE Plastic Check Valve Housing
  • Supports Boost Pressures to 40+ PSI
  • Compatible with OEM and Upgraded Turbocharger Inlets
  • CNC-Machined, Billet Aluminium Check Valve Body (Black Anodized), with a Heat and Chemical Resistant, Durable Rubber Diaphragm
  • 4-Ply, Reinforced, Silicone Hose
  • Retains Factory Engine Cover
  • Simple Installation

Fitment:

* 034-101-3108 is for B9 3.0T engines such as S4/S5/SQ5 does not fit the 2.9TT which is 034-101-3109.

Make Model Years Chassis Engine Note
Audi A6 2019-Present C8 3.0 TFSI Select: B9/B9.5/C8 3.0T Engines
Audi A7 2019-Present C8 3.0 TFSI Select: B9/B9.5/C8 3.0T Engines
Audi allroad 2019-Present C8 3.0 TFSI Select: B9/B9.5/C8 3.0T Engines
Audi S4 2017-Present B9/B9.5 3.0 TFSI Select: B9/B9.5/C8 3.0T Engines
Audi S5 2017-Present B9/B9.5 3.0 TFSI Select: B9/B9.5/C8 3.0T Engines
Audi SQ5 2017-Present B9/B9.5 3.0 TFSI Select: B9/B9.5/C8 3.0T Engines
Audi S6 2019-Present C8 2.9 TFSI Select: B9/B9.5/C8 2.9T Engines    
Audi S7 2019-Present C8 2.9 TFSI Select: B9/B9.5/C8 2.9T Engines    
Audi RS4 2018-Present B9/B9.5 2.9 TFSI Select: B9/B9.5/C8 2.9T Engines    
Audi RS5 2018-Present B9/B9.5 2.9 TFSI Select: B9/B9.5/C8 2.9T Engines    

 

The installation of your 034Motorsport PCV Breather Hose, EA839 2.9T/3.0T is a straighforward process that should take approximately 1 hour or less to complete. You can access our detailed installation guide by clicking the link below.

Download the 034Motorsport PCV Breather Hose, EA839 2.9T/3.0T Install Guide

Recommended product: Audi B9 S4 ECU Tuning
Recommended product: Audi B9 S5 ECU Tuning

Shipping Notes
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Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
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SKU: 69785357549

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4.6 ★★★★★
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M.K.
Grantham, US
★★★★★ 4
Durable, interesting, but not my dog's favorite.
Color: Purple, Size: Large (Pack of 1)
This is a pretty cool treat dispensing toy; the rubber it's made from is very thick and durable, and the irregular shape of it makes it more interesting for the dog. The opening of each compartment has little strips inside that makes the toy dispense treats pretty randomly. You can also snip them so they're shorter, to dispense treats easier. I snipped all of them in my toy, because my dog was having a hard time getting treats out, and I adjusted them several times to where now it's almost too easy to get the treats out. I just couldn't find a happy medium, and of course once you've cut them, you can't uncut them. The only real down side to this toy is that it collects dog fur and can get pretty gross pretty fast. Most of my dog's other toys stay relatively clean when she's using them, but between the material and the pattern and whatnot on the outside, this toy is just a gunk magnet. Fur collects in the little dips between "barnacles" and clings to the slots on the outside of the toy. My dog doesn't really mind, obviously, but I think it's a little gross. ;D My dog for whatever reason favors most of her other toys over this one; even when this is the only toy that still has treats left in it, she'll often ignore it. It's a very high quality toy, though.
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Reviewed in the United States on July 24, 2015
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inventurous
West Palm Beach, US
★★★★★ 5
Durable and Fun Diversion!
Color: Purple, Size: Large (Pack of 1)
At first I was a bit concerned as the toy is made of a fairly pliable rubber so I worried that my vizsla, who destroys most of his toys rather quickly, would destroy this one within hours. Luckily, I was able to quickly teach him that it's much more fun to carry and kick around, then to gnaw. So far it's been over a month that I've actually left this on the floor, and it shows very little signs of damage. Some treats have made a perpetual home in the large and medium sides of the toy, and it keeps him interested from time to time, as he'll just randomly pick it up and start kicking it around, or bring it to me in hopes of a game of fetch or a treat reload. One thing that definitely helped him fall in love with it was that I immediately (after washing) placed a variety of sizes of his favorite treats in the different globes. Some (kibble-sized) treats fell out easily and taught him that this was indeed a rewarding toy to play with, others took a little kicking and dropping, and some remain until they start to break apart from enough bouncing and licking, which keeps his attention. We have the large (for a 40-lb dog) and it suits him well as he can get his mouth around even the largest of the globes to carry it, while it has about a zero percent change of becoming a choking hazard, unless a piece breaks off, which seems unlikely so far. One does have to be somewhat careful playing fetch in the house, as it bounces somewhat unpredictably and has a bit of heft to it. Very pleasantly surprised to find that the rubber actually smells good, somewhat like bubble gum, as opposed to some other rubber toys that reek of chemicals. Overall, very happy with the durability, safety, and fun of this one, and wouldn't hesitate to replace it with the exact item if it is ever lost or damaged.
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Reviewed in the United States on November 24, 2014
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E. Ricciardi Trundy
Chelsea, US
★★★★★ 3
3.5 Stars -- Sturdy but Limited
Color: Purple, Size: Large (Pack of 1)
I got the Barnacle toy in size Large for my ~45 lb mutt. She enjoys food toys, and I wanted to find one sturdy enough that I felt safe leaving her with when I left for work since she tends to destroy her toys quickly. First thing -- there's no way any dog is going to be able to destroy this. The "rubber" is super thick and a good balance of flexible and sturdy, so she can't do her favorite "pick at a weak edge and slowly disembowel it" trick. I've had it for a couple months now and it looks brand new. However, it isn't great for feeding her kibble. She eats 1 cup at morning and at night, and none of the compartments fits that comfortably. I don't really feel like dividing her food into 3 portions every day to split it between either. The bigger problem is the hole size, or rather the ratio of kibble-to-hole size. The holes are very big with rubber "fingers" inside to slow the food spill. I've still found that it tends to dump a fistful of kibble all at once, or not let anything go for a long time. This may have to do with my dog's "technique", as described below. Another problem is that since this has three separate chambers, this toy is not hollow and is surprisingly heavy. While my dog has no problems throwing a kong around (and I mean THROWING a kong around), the weight and asymmetrical shape makes it difficult to throw or roll, which is my dog's preferred way to use a food toy. This toy works best when a dog slaps it with her paws or picks it up and drops it, which may be why my dog gets frustrated with getting her food from it. What this toy is really great for, for us, is high value treats. If I am leaving at an unusual time and anticipate that she's going to fuss, I can put "the good stuff" in this toy and then she doesn't mind the struggle at all! The different size chambers make this especially nice if I'm breaking up odd sized or home made treats and want her to stay busy for a while. Since it's so sturdy, she can chew on it all she wants, but she has to do the work to get the treats. All in all-- this toy isn't great for my dog's daily feedings, but it's great for high value treats and a change of pace.
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Reviewed in the United States on March 2, 2015
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Write Reviews
Massapequa, US
★★★★★ 5
Actually a challenge for my genius dog!
Color: Purple, Size: Large (Pack of 1)
I am pretty sure my dog owns every puzzle toy and treat-dispensing dog toy that exists, and he's able to figure most of them out in less than 5 minutes. Many last no more than 60 seconds before he's solved them. The Barncle, however, is actually a challenge for him! The Barnacle has three "compartments, " none of which are connected. All three have a rubber "mouth" that helps keep treats inside. The rubber "mouth parts" are very effective and make it quite challenging to get treats out once they've been placed inside. You can trim the rubber "mouth parts" to make it easier to let treats out, but I'm not doing that. I'm glad that it's not challenge! The Barnacle keeps my dog occupied for at least 30 minutes, which is a LONG time for my dog who usually has a "What next?" attitude towards toys. Th only "bad" thing about the Barnacle is that it's so hard to get treats out of, even for humans. Therefore, it could attract vermin if you're not careful to clean it out.
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Reviewed in the United States on May 20, 2025
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Vanessa
New York, US
★★★★★ 1
OMG - DO NOT BUY - it smells like noxious poison.
Color: Purple, Size: Medium (Pack of 1), Color: Purple, Size: Medium (Pack of 1)
OMG DO NOT BUY!!!!!!!!!!! I didn’t think the reviews stating the noxious smell could be accurate - OMG OUR WHOLE HOUSE REEKS OF POISON. I LITERALLY FEEL LIKE I MAY BE SICK. OMG OMG OMG.
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Reviewed in the United States on April 11, 2026

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