We've noticed in our own service repair facility that the Audi A4 V6 30 valve 2.8 liter engines can develop oil leaks as the car gets older and advanced in miles. Repeated attempts are made to stop the leaking by replacing multiple gaskets and seals. Before you go through the repair costs of having these seals and gaskets replaced, Blauparts would like to bring to your attention a prominent issue with the Audi A4 crankcase breather hose system.
Many Audi A4's have a rough service history. We consider 'rough' to be irregular oil changes, extreme hot or cold climates, a lot of short driving distances where full engine temperature is never reached, and excessive low RPM city driving. This produces a great deal of condensation and moisture to form within the engine, causing a build up of sludge. Many owners have bought an Audi A4 without knowing the oil change and driving history. If you own or have just bought an Audi A4 with over a 100,000 miles that has oil leaks, the crankcase breather system should be treated as suspect. If you remove the valve cover and see a lot of resinous accumulation in the valve train area, this indicates that the vehicle already has heavy amounts of oil sludge build up throughout the engine. Suspect number one is the Audi A4 crankcase breather system.
Years of rough service history as mentioned above, cause contamination to take place inside the engine which clogs the Audi A4 crankcase breather hose system. Due to this blockage, the air flow generated within the engine crankcase is restricted and will not allow the system to breath properly. When the engine is running, pressure builds up in the crankcase and causes oil to push out and leak from the weakest parts of the engine.
To check the condition of your Audi A4 crankcase breather hose system follow the steps below. This will help you determine whether your oil leak(s) could be caused by a plugged or restricted Audi A4 crankcase breather hose system.
If the inside of your Audi A4 crankcase breather hose system looks to be restricted with oil sludge deposits, it's likely that the pressure control valve, check valve and suction pump are also plugged. You can remove the valves and lightly blow through them to check if they're restricted or clogged.
- Remove the fasteners that hold the coolant expansion tank in place. Unplug the level sensor on the bottom and place the tank off to the side leaving the coolant hoses connected.
- Remove the center and drivers side decorative engine covers.
- Locate the Audi A4 crankcase breather hose on the backside of the drivers side valve cover. To slide the Audi A4 breather hoses off, compress the two pressure finger clips and gently pull out. Be careful! As the car gets older and advanced in miles, the years of high engine temperatures (under the hood) can cause the crankcase breather hoses to become brittle and easily breakable. (See images below)