I finally got the 83 cooled down at highway speeds. I had flushed it a couple of times. but today I pulled the bottom and top hose, stuck a garden hose in the top and let it go for about 1/2 hr. I was getting algae out of it. My guess is the PO had left it sit for a period of time with nothing but water in it. On the outside, it looks to be a fairly new replacement. I also pulled the tstat till I can figure a way to clear the rest(if any) of the growth out. Any ideas? I'm thinking maybe running a strong bleach solution through just the radiator

__________________
81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

I don't see how algae could be growing in there with no light.

__________________
1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver

1982 300SD - 232K miles - Wife's Daily Driver

1986 560SL - Wife's red speed machine

Hmm, probably not alge... perhaps there is some brass in the system somewhere? hmm, I wonder what it is.
John

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

It was coming out in pieces but you could tell it had been in a thin layer, kinda sheet like. It was very dark, almost black but when I spread it across my hand it was green.

__________________
81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

Sounds like the PO used the green anti-gel. How many years since last change? Since there is plenty of good size pieces, this will have the effect of blocking the coils in the radaitor. Maybe if you back flush it, force water through the bottom outlet, will remove the deposits. Other wise, a cirtrus flush is in order, do not know this will remove the green scum....

Bill

Understand MB is using vinegar to flush cooling system

I thought of doing that, but decided to flush with clear water first. What you suggest would work for scale and calcium, wife does it all the time with the coffee pot. I don't feel it would work for algea if that is what this it.

__________________
81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

I'd recommend a citric acid flush.

After finding the green stuff in my 300D, I drained the cooling system, flushed it several times with water and then with a Zerex cleaning product (which I left in for a week) and finally again with several more rounds of water. Just as things were looking pretty good, I decided to do a citric flush as well, just in case.

Well, when I drained that, the stuff that came out was all the sudden bright green again -- as green as when I drained the system at first. I had to flush it several more times with water before it stopped coming out green. It seems like that green crap must have been clinging to every surface of the system and required the citric acid to finally scrub it out.

Also, when draining the system, make sure to use the block drain as well as the radiator drain; otherwise the majority of the fluid remains in the block.

ok I'm stupid......what is it and where do I get it?

__________________
81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

You sure that was algae and not oil?

think of a rock that has been underwater till it get a layer of slime on it, then taken out of the water and allowed to dry. that thin membrane that is left behind is what appears to be in the cooling system. it looks very dark, almost black, byt when smeared on a light surface is green. I don't believe it is oil and I have not had any oil droplets in the bucket when I drain.

__________________
81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

ok u got to it before me but, i was gonna say are u sure that the oil didnt sit in ur radiator and clump to gether after time " not good" if u easily want to do a citric acid flush, u can go to ur local wally-world or parts store and buy that prestone radiator flush, it contains citric acid just like the mb stuff, just drain ur antifreeze, pour it in, then top off with water, then drive around for a while to get it good and hot, the just drain etc...

__________________
82' 300SD

Maybe its a critter that does'nt need light. Like the stuff that grows in fuel tanks.

__________________
a few mb diesels

I did the prestone 3 times in the past month....anything better?
what if I used bleach and water? yep, I'm to that point

__________________
81 Mercedes 300SD 289k.......SOLD
82 Mercedes 300CD 252k......slow ride

82 mercedes 300 SD...mi Unknown
83 Mercedes 300D ????ksniff..gone too
84 Mercedes 300D 148k........SOLD
85 Mercedes 300TD 386k and holding some one elses project

i think u would be alright, just dont keep it in there for to long and make sure u flush it pretty good sfter doing it.
I dont know waht the bleach would do when heated up though, someone else might want to chime in on that one.

__________________
82' 300SD