Seattle Scott

I decided to change my antifreeze after receiving various opinions that it should be changed at regular intervals (Thanks Guys). So I looked at my Bentley manual, read the procedure and went out to the garage to "dry lab" it today. Well, the Bently procedure would be nice if I had the special tool, could find everything, and had fingers that were 20 inches longs that could crush walnuts.

So here is what I'm thinking of doing :

1. Remove bottom engine shield.
2. Get engine up to operating temperature.
3. Pull lower radiator hose at the water pump (Front of engine, passenger side).
4. Pull lower expansion tank hose at bottom, front of engine. (There are various hoses and a long pipe that run in front, bottom of the engine).
5. Let it all drain.
6. Re-attach hoses.
7. Refill with de-ionized water.

Hopefully skip bleeding/venting. I really want advice here, preferably from people that have worked on this engine.

8. Get engine up to operating temperature and run for a while while monitoring coolant level and temperature.
9. Drain it all again.
10. Probably repeat the flush with de-ionized water.
11. Add coolant (antifreeze and de-ionized water).
12. Install bottom engine shield.

Points of interest/questions :

The Bentley manual says you need "Special Tool 3247" to drain the radiator and engine. This must be a neat tool, I looked inside the radiator drain "tunnel" (passenger side, bottom corner, under the lower radiator hose), saw blue plastic inside, can't figure out what goes on in there. Spring loaded petcock?

I never looked, but I don't know where the coolant drain for the engine is, any hints?

I only found one of the two bleeder screws listed in the manual.

I found the bleeder in the large cooling pipe at the back of the engine, driver side (next to the Coolant Temperature Sensor). What do you use to get at that thing? A super long hex wrench? Remove something first? Go from the side?

There is also supposed to be a bleeder screw in a heater core hose next to the brake booster. I don't see it/can't find it.

Do you even need to bleed (vent) these engines when refilling? Would jacking up the left front get me there?

Any comments / jokes welcome.

Thanks,
SS

Kenny

Yes, bleeding the coolant system on German cars is very important... Sometimes you have to bleed these cars several times to get the air pockets out of the car... These air pockets can prematurely cause the engine to overheat...