Audi 7A engine "remove crankcase ventilation hose at engine block and plug off"

[cgharibo]

I have a 1991 coupe with the 7A engine, the Bentley states "remove crankcase ventilation hose at engine block and plug off".

Where is this done best? There is about a 2" crankcase breather hose that connects to the engine. Is this the hose that I remove? What do you use to plug off at the engine? It's a huge opening. A picture would be great!

Thanks!

[Lago Blue]

Hi Sir.

IIUC, you have a "late" car (correct?), which may have 2 hoses (2nd drwg) running from that big CCV hose connection boss you've located on the left side of the block (1st drwg); temporary clamp is shown (looking down into engine bay from above and forward of FPR) on an early car (3rd drwg):

7A LH side drwg showing CCV boss below & aft of FPR.png 7A late, CCV hoses schematic.png 7A early, CCV hose temporary clamp near block connection, .png

At least one of those hoses may be a metal tube where it runs parallel to the firewall, so yes (lacking suitable clamps) corking the removed hose end with something will suffice; if the hoses are in good shape. Something like a capped piece of pipe or a tapered rubber plug suitably matched to the hose ID would work.

Are you doing the idle?

[cgharibo]

Yes, I have the later 7A and I am doing the idle. I have a much better idea now. Thank you!

Is anyone aware of an attachment that I can install that blocks off the 32 mm crankcase breather hose without removing the hose?

Thank you, everyone!

[Lago Blue]

CG,

I have an early car. Is it not correct that the later cars don't require that CCV blocking procedure?

http://www.20v.org/engprob.htm#idleadj

[cgharibo]

I saw that at 20v.org. However, Bentley for late 7A cars still advises CCV hose blocking.

[steve briance]

I've often wondered about fitting a full bore 22mm isolating valve somewhere in the length of metal pipe that runs from crankcase along the back of the engine. Full bore meaning that the 'open' hole is 22mm rather than the somewhat more restrictive standard valves. With one in place, a simple twist of a screwdriver closes off engine breathing to the air intake hose.

I can't see a downside other than I don't have one on my car! It's a balancing act... The work involved fitting one and how easy it then becomes to clamp off engine breathing vs how often do you check your Idle and CO mixture?...

[Lago Blue]

Seen these from Harbour Freight and perhaps the FLAPS nearest you? Perhaps the 45mm one would suffice?

Hose pinching clamps.png

[steve briance]

Sadly They won't work on the metal replacement for the mushy rubber breather pipe I've got that much needed mod on mine and you only get 2inches of rubber hose before it goes off and joins the metal pipe behind the cylinder head.