w210 . 606 coolant replacement question
 

I drained almost exactley 2 gallons of coolant from my 210.606 this morning from the radiator only not the block drain. When I was refilling only 1 gallon went back in. I started the car and let the engine warm thinking that I could add some more when it got to operational temp. It very quickley went over 100C. At this point I shut it off thinking that there is an air bubble somewhere. I felt fluid in the lower hose but the upper hose was completely empty. I disconnected the top radiator hose and filled it until I culd no longer. It took an additional .5 gallons. The car is still running much hotter than normal.

What did I do wrong?

I used MB fluid and 1 bottle of WaterWetter.

You should ensure that you drain the entire system.

Thanks, Blackmercedes. Time was a limitting factor today as it is every day. Since I drained approx. two gallons and the fluid "looked" almost new (ie. no settlement, origional color etc...I know all about oxidation) I passed on the block drain.

Are you saying that the fact that I did not drain the block has resulted in overheating?

If so:

1) Why has this never happened to me before?

2) How do I correct?

Somehow you have introduced air into the system, and I think it is by not draining the system completely and refilling to ensure no air pockets. Your cooling system lost two gallons (about 7.5L) and you only put back one. Your system is down on coolant by quite a bit.

Also, why the Wetter? The 606 in the W210 doesn't run hot at all. Even in 40C weather with the AC blasting our E300 ran below 100C every time.