Coolant leak from rear of engine? Dripping around transmission area?

[Blue AWD]

Going to get it on a lift later but anywhere to check? It's a slow leak. It seems to be dripping down onto the transmission.

Any insight on where to look would be great. Thanks.

[komseh]

Could be the vent hose running across the back of the IM...

Or it could be one of the seals on the main coolant pipe back there :(

[Blue AWD]

I assume the seals on the coolant pipe require removing the engine?

[komseh]

Nah there's clearance to get at the necessary fasteners.

Paste from bentley manual:

Audi > A4, S4 (B6, B7) > 2002-2008
4.2 Liter V8 4V Engine Mechanical, Engine Code(s): BNS
19 - Removal and Installation.Rear Coolant LineSpecial tools, testers and auxiliary items required
Spring-type clip pliers VAS 5024 A
Removing
Note:
During installation, re-install all heat insulation sleeves and heat shields at the same locations.
All cable ties opened or cut during engine removal must be reinstalled at the same locations during installation.
Drain coolant. Refer to Cooling System, Draining and Filling .
Remove bolts - 1 - and - 5 - at bottom of left secondary air injection combination valve.
Note:
The illustration depicts the engine removed from behind.
Ignore items - 2 to 4 - .
Bend heat shield slightly to side.
Disconnect electrical connector on Engine Speed (RPM) Sensor G28 - arrow - .
Remove coolant hose - arrow - to heater core on rear coolant pipe.
Remove heat shield - 1 - for right drive axle.
Remove drive axle from transmission flanged shaft.
Remove bolts - 4 - and - 5 - at bottom of right secondary air injection combination valve.
Note:
The illustration depicts the engine removed from behind.
Ignore items - 1 to 3 - .
Disconnect electrical connector - 1 - on Engine Coolant Temperature (ECT) Sensor G62 - 2 - .
Remove intake manifold. Refer to Fuel Injection and Ignition - Repair Group 24
Remove left secondary air injection combination valve and lay it aside with vacuum line connected.
Remove rubber seal and remove plenum chamber cover - 1 - forward - arrows - .
Pry off cover caps - 3 - from wiper arms with a screwdriver.
Loosen nuts - 4 - several turns.
Loosen wiper arms - 2 - one after another by tilting wiper axles slightly.
Remove nuts completely and remove wiper arms.
Note:
If wiper arm cannot be removed in this way, use a standard puller.
Disconnect securing clips - 1 - and remove cowl grille - 5 - .
Remove cover for E-Box in plenum chamber - arrows - .
Using a screwdriver, carefully pry off mounting bracket - arrow - and remove Engine Control Module from E-Box.
Note:
Engine Control Module remains connected at wiring harness.
Release retaining hooks - arrows - toward outside and remove retaining bracket.
Disconnect all electrical harness connectors on connector station - 2 - .
Remove electrical wire connection - 1 - .
Disengage locking mechanisms - arrows - and remove secondary relay carrier in E-Box toward top.
Disengage engine wiring harness at E-Box and bulkhead.
Disconnect electrical connectors - 1 - and - 2 - .
Free up wiring harness.
Set electrical wiring harness on engine and secure Engine Control Module against falling down.
Remove bolts - 1 - and - 3 - .
Remove coolant hose - 2 - to coolant connections.
Slide heat insulation sleeves - arrows - over left and right coolant connection hoses at rear coolant pipe to side.
Loosen hose clips with Spring Type Clip Pliers VAS 5024 A and slide coolant connection hoses to side.
Remove electrical connectors - 4 - and - 5 - from bracket at rear coolant pipe.
Remove rear coolant pipe to left.
Installing
Installation is in reverse order of removal, note the following:
Note:
Replace O-rings.
Secure all hose connections using hose clamps appropriate for the model type. Refer to Electronic Parts Catalog ETKA .
During installation, re-install all heat insulation sleeves and heat shields at the same locations.
During installation, all cable ties must be re-installed at the same location.
Clean and/or smooth O-rings sealing surface before installing.
Coat new O-rings with non-corrosive lubricant (Vaseline), install rear coolant pipe and tighten.
Install secondary air injection combination valve. Refer to : Left Left Secondary Air Injection Combination Valve , right Right Secondary Air Injection Combination Valve .
Install intake manifold. Refer to Fuel Injection and Ignition - Repair Group 24
Mount wiper arms and adjust. Refer to Electrical Equipment - Repair Group 92 .
Fill with coolant Filling .
Tightening Specifications
Component Nm
Rear coolant pipe to cylinder head 9
Heat shield for drive axle to transmission 23
Copyright © 2008 Audi of America, Inc. and Bentley Publishers. All rights reserved. Last processed:

[Blue AWD]

Looks like fun! Thanks for the info.