Rusty coolant
 

I noticed the last owner or the one before him must had ran some straight water, when I drained the radiator and block I noticed a lot of corrosion, surface rust in the coolant passages and pipes. :confused:

So I was wondering if anyone here had some ideas? one idea was to run baking soda or vinegar for 10-20 mins and then flush that, I have distilled water here. I know some folks have used wood varnish and all, but I wanted to check with you guys, as this is my first M44 and I dont want anything to go attack other engine components eg. head gasket or anything because I ran vinegar or anything like that.

ideas?

So I ran vinegar for a bit, ran it, left it there overnight, drove it a bit. I had about 3L of vinegar in there, rest was distilled water. The drained water vinegar mixture was a bit rusty.

Then I neutralized the remainder vinegar by using some baking soda, I used 4 tea spoons, should had used half that. foamed up quick and at one point was quite pressurized as expected and the little bleeding screw hole became a volcano at operating temps. I then proceeded to clean it up with tap water from the hose, about 20L of that later, what came out was just as clean as what went in. At this stage I was done and added distilled water + green nulon coolant. bleed it. Hopefully this takes care of it. :D

I had similar situation. unbolted the head drain plug and thought "crap I unbolted the wrong bolt", cause nothing came out. Had to poke in there to get it to flow it had rusted over so.

I did the vinegar, but just through the head bit with everything off. I used a pipe cleaner thing to reach what I could and flushed it all. So didn't run the diluted vinegar through the whole system. It was while I was replacing everything. That was 2013ish and my coolant is still Blue today.