d00012

I'm trying to drain the coolant in my S6 so I can remove the expansion tank. I'm not seeing any kind of petcock to drain the coolant. I don't want to make a huge mess, but will if I have to.

Any suggestions?

Thank you!

A6 4.2 Vier

On my 2007 A6 4.2l, I just pull the lower radiator hose from the thermostat housing with a suitable size container below. It is much quicker than loosening the bleed screw.

d00012

I'm not in any rush to get this done, so I want that option to be my last resort. I don't need all the coolant drained, just enough so I can remove the expansion tank and get to the valve cover easier.

A6 4.2 Vier

Unfortunately you still need to remove a fair amout of coolant to empty the expansion tank. If you try removing just the lower hose to the expansion tank there is minimal room to properly drain in a container without making a mess.

If room allows you may be able to swing the expansion tank out of the way, I don't know if this is douable with the V10.

d00012

Never said I was going to pull the hose from the expansion tank to drain it, like I said, I'm looking for the less messy option, and was hoping there was a drain/petcock like most other vehicles.

No, it's not easily doable with the V10, the lower hose is too short for it to move anywhere to give me easier access. I've tried.

jseklund

If all you want to do is remove the reservoir, a set of these could help while preventing a need to refill and bleed the system. Not sure of the setup for your engine, but my reservoir only has one large and one small hose coming off. These will clamp those shut so you can pull them off with minimal fluid loss.....

https://www.harborfreight.com/4-piec...xoCnPMQAvD_BwE

You.could also use a pump to just pump out the reservoir before you clamp the hoses.

Just another way of looking at it I guess.

kelisko

1. Disconnect the coolant return line.
2. Attach a flexible tube long enough to lead the extension to the floor, into a bottle.
3. Remove the coolant tank and tilt it up above the disconnected return line height. Coolant from the tank will be evacuated to the bottle on the floor.

The following video will give you an idea.

A6 4.2 Vier

There is a bleed screw on the thermostat housing if you have the patience to drain it down this way, unfortunately there is no drain on the radiator.

jseklund

Haha - your 3 line explanation was faster and more thorough than the 14 minute videos that you linked! Good idea....I should have thought of that too.

Klaus Von Richter

I just had to replace the coolant tank on my 2008 S6. I used a fluid extractor to remove the coolant from the expansion tank. You have to remove the entire passenger air filter housing to access the coolant tank level switch and lower coolant tank hose.

it’s pretty tight on the 5.2 V10 but you can work the coolant tank out once the air filter housing is removed. Best of luck.