Free Shipping over $99! Lifetime Replacement Program

310-626-8765

Pelican Parts Technical Articles Main Image

Audi A4 B6 Crankcase Ventilation, EGR Hoses and Valve Replacement

Applicable Models
Jump to Photos
9 Comments

Applicable Models:

Placeholder alt text

Placeholder alt text

Audi A4 (2002-05)
Audi A4 Cabriolet (2003-06):
- A4, A4 Quattro, S4, (2002-2005)
- A4, A4 Quattro, S4, RS4 (2005-2011)

Rennline Performance Products

Lifetime Replacement Parts

Pelican Parts Tech Forums

Project Time: 1-6 hours
Tab: $1 to $200
Talent
Tools: Pliers, screwdriver, sharp knife

Parts Required: New hoses and valve
Performance Gain: Car runs like normal again
Complementary Modification: Replace vacuum hoses

The Audi A4, like most modern cars, runs with very strict regulations on pollutants while still trying to get every mile per gallon it can from fuel.

The engine is designed to use the vacuum pressure created by the pistons to assist in the fuel injection, turbo and emission systems.

If the vacuum system starts failing, you can have problems ranging from a rough running engine, poor mileage to failing a SMOG test. While this article is not meant as a complete breakdown of the design and implementation of the engine and its vacuum related components, it is more of a guide to point out the hose, valves and fasteners used to keep the system running correctly. When trouble shooting the system, a pressurized test is really the only way to verify minor leaks, but you can check each hose and connection for trouble. With the hoses look for dried, cracked or split hoses. Hoses with bulges are failing and should be replaced. Hoses that are cracked or drying out should also be replaced. A hose should be soft to the touch and easily compress when squeezed and then spring back out to its original shape.

Hot tip

Use caution working with old hoses

Wayne R. Dempsey, Co-Founder & DIY Expert

Steve Vernon, DIY Expert

//

Project Photos

Placeholder Alt Text — Figure 1 There are a series of hoses and a valve making up the vacuum and emission systems on the vehicle. The main areas to check are above the intake air cleaner (red arrow), to the right side of the rear of the engine cover (yellow arrow), and to the rear of the intake manifold (green arrow) and the intake manifold itself.

Placeholder Alt Text — Figure 2 The area to the rear of the intake air box contains the EVAP valve (red arrow) and lines (yellow arrow). If the EVAP valve is throwing an error code, it is best to just replace it. The lines should be checked for condition and replaced as needed. The hose clamps used from the factory need a special tool to reuse. Most people just pry the clamp off with a screwdriver and replace the clamp with a standard hose clamp.

Placeholder Alt Text — Figure 3 In front of and below the intake air box is the secondary air pump (red arrow). There are two plastic lines that will split when cracked.

Placeholder Alt Text — Figure 4 The secondary air pumps intake line connects to the air box (red arrow). The output line connects to the crankcase breather (PCV) valve (yellow arrow).

Placeholder Alt Text — Figure 5 At the rear of the engine you will find the crankase breather (PCV) valve (red arrow) and s series of hoses and valves for the EGR system (yellow arrow). The lines should be checked for condition and replaced as needed. The hose clamps used from the factory need a special tool to reuse. Most people just pry the clamp off with a screwdriver and replace the clamp with a standard hose clamp.

Placeholder Alt Text — Figure 6 The intake manifold has a series of vacuum and EGR hoses attached to it. On the rear is a line that connects to the EGR system. Like most of the hoses, it came from the factory with a clamp that is very difficult to reuse (red arrow). If you are ordering new hoses you should also be getting new clamps to be on the safe side.

Placeholder Alt Text — Figure 7 There is a vacuum line on the right side of the manifold (red arrow). This hose has been worked on before and already had the clamp replaced.

Placeholder Alt Text — Figure 8 While the gasket that seals the crankcase ventilation valve is not as critical as a fuel seal, it is always a good idea to replace it (red arrow). These gaskets get old and dry up and leak over time.

Placeholder Alt Text — Figure 9 With the intake manifold removed you can see the crankcase breather hose (red arrow) and the turbocharger recirculating valve (yellow arrow) and the secondary air injector solenoid (green arrow). The lines should be checked for condition and replaced as needed. The hose clamps used from the factory need a special tool to reuse. Most people just pry the clamp off with a screwdriver and replace the clamp with a standard hose clamp. These hoses and valves are all mounted below the intake manifold and cannot be serviced without first removing the manifold.

Placeholder Alt Text — Figure 10 While the clamp that seals the crankcase ventilation valve is not as critical as a fuel seal, it is always a good idea to replace it (red arrow). This hose gets old and dry ups and leaks over time.

Comments and Suggestions

Helen

December 4, 2023

What is the part called? I have audi a4 b7 cabriolet

Followup from the Pelican Staff:

That is the vacuum check valve breather hose assembly. With your vehicle info handy, give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need. - Nick at Pelican Parts

Placeholder Alt Text

Deb

April 20, 2023

2000 Audi A4 Quattro 1.8 l Manual
Figure nine the two braided hoses left of the yellow and green arrows are disconnected on the other end. I do need to replace but have no idea where go. I tried to attach a picture of where I thought one connected to but it didn't work.

Followup from the Pelican Staff:

The short hose with the curve goes to the intake manifold and the longer one goes to the turbo vacuum diaphragm for boost. - Nick at Pelican Parts

Molefe

October 20, 2022

I have a b7 1.8t, engine is misfiring,I changed the crank case breather and it was better,I then drove for 200km,when I stopped,I realized that the pcv is broken again,it seems as if there's a blockage in the vacuum system, please assist

Followup from the Pelican Staff:

You can check for a blockage by detaching the breather system and checking for flow on each side. Vacuum at the intake, pressure at the crankcase. - Nick at Pelican Parts

Col

November 18, 2021

Hi what are the valves and their part numbers in fig 5, please. The series of hoses and valves for the EGR system yellow arrow.

Followup from the Pelican Staff:

You didn't mention what year and model vehicle you are working on. With your vehicle info handy, give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need. - Nick at Pelican Parts

robert g

July 5, 2018

i understand the system but i need to ask i have my car b6 engine but it has some problem if i start the car it start nicely and when i engage in gear it doesnt pick up speed it goes slowly without speed its a manuel i thought it was the hanners bt steel have the same problem help am about to sell the car becouse of that i realy need the car

Followup from the Pelican Staff:

Check exhaust backpressure. Could be too high. - Nick at Pelican Parts

v.adrian

May 27, 2018

On this system there is no EGR system as the engine have a VCT system.Stage 4 emmision engines with VCT have no EGR system. The vacuum lines with that valve that you are calling EGR is a venturi pump for generating more vacuum for breake booster. Special care should take to that venturi pump and PCV valve under intake manifold. The venturi should block pressure as engine runs under boost, can loose boost if escapes under boost.

Followup from the Pelican Staff:

You are correct, thanks for catching that. I think there was a typo that kept repeating itself. I will confirm with the author and see what can be fixed. Thanks again. - Nick at Pelican Parts

Jared

June 24, 2017

On figure 9, the turbo recirc valve and the second inj sol, they have vacuum lines coming off them. Where do those lines go to?

Followup from the Pelican Staff:

the pressure valve line goes to a solenoid, and the inj solenoid line goes either to the intake or the secondary air valve. - Nick at Pelican Parts

avishai

December 25, 2016

hi
i have Audi a4 2003 1.8t vin-WAUZZZ8E53A023772
i neet to know if you have all pipes and valve for vacum system and thr cost of it including p.p to israel please
thank you

Followup from the Pelican Staff:

Pelican Parts has them. Give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need. - Nick at Pelican Parts

Matthew

March 30, 2016

Hi I'd like to order the hose for the EGR system, but I can't find it on your website

Followup from the Pelican Staff:

You didn't mention what vehicle you have. For an instant response, give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need. - Nick at Pelican Parts

Got more questions? Ask any of our automotive experts.

Technical Forum Message Board Reader Questions About this Article

Applicable Models:

Audi A4 (2002-05)
Audi A4 Cabriolet (2003-06):
- A4, A4 Quattro, S4, (2002-2005)
- A4, A4 Quattro, S4, RS4 (2005-2011)

Placeholder Alt Text

Placeholder Alt Text