Interesting. You may have to use the vacuum tool to get it bleed. Here are the parts for the cooling system. See the attached pictures. The following indicates parts/numbers which are related to picture 1. Item 23 goes to the expansion tank (reservoir) which is indicated to be on the rear of the engine. Picture 3 shows the front of the engine (exploded view).
I have to be honest, I have worked on several 4.2L A8 vehicles. The cooling system runs everywhere around the engine. With that, what I think we may need to try is to first loosen the upper radiator hose to allow air to escape the radiator. Once coolant starts coming out, move to the heater core return. If you still can't get coolant throughout the system, you may have to get the tool.
1 Coolant line
Between right and left cylinder head
With junction to heat exchanger for heater, expansion tank and upper coolant hose.
2 O-ring
Replace
3 Engine Coolant Temperature (ECT) Sensor (G62)
With Engine Coolant Temperature (ECT) Gauge Sensor (G2)
For engine control module
If necessary release pressure in cooling system before removing
4 Coolant line
5 To coolant thermostat
6 20 Nm
7 Gasket
8 Coolant line
From cylinder head, bank 1
9 Coolant line
To oil filter housing
10 To expansion tank
11 To expansion tank
12 Coolant line
13 10 Nm
14 To top coolant hose
15 10 Nm
16 Side coolant pipe
At cylinder head bank 1
17 Coolant hose
18 From heat exchanger for heater unit
19 To heat exchanger for heater unit
20 Coolant line
21 10 Nm
22 Retaining clip
Check for secure seat
23 Connection
To expansion tank
24 10 Nm
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Let me know if any of this helps.
Joe
Monday, March 4th, 2019 AT 8:08 PM
