"black" coolant anti-freeze

[yachtsmanbill]

Drain and capture ALL the coolant. Let it separate, flush system, and re-install with new additives and make-up level to full. In my opinion, DDs dont circulate the coolant at a fast rate, and have a tendency to sludge up, especially down LOW !! ws

[MikeP]

I guess everyone has their own views but I would never put that stuff back into the engine, no matter how much I settled and filtered it.

[yachtsmanbill]

I guess the point I was try to get across, is that if the stuff is Power Cool or equivalant, its probably re-useable. Especially if the mud settles out so easily. I think the guy needs a serious flush, but if he's cheap like me... ;-)
Thirty gallons of AF in europe is a lot to throw away IMHO...
When I changed mine last year, I pulled the valves out to facilitate letting the force carry the mud away with the juice. The manifolds were the worst culprit and each had about 2-3 oz of gunk on each. 'Ol Bessie runs ALL DAY at 180F, but then its not a space shuttle engine like some of the members have here LOL...I know, I know... the clocks ticking away on the old Ns... probably less than 5000 hours left on them before I attempt the forbidden in frame rebuilds. If only I could in Perfectville, life would be good; but then again, life here on Desparation Alley is kinda OK. I'm gonna go FRY some Tilapia in REAL BUTTER for dinner, and have a smoke afterwards.
Ahhh ! ws

[stormchaser]

I've have been doing some research and i have found that mixing non-compatible types of antifreeze can produce brown sludge like what you are describing. Perhaps someone previously added coolant/antifreeze that was not compatible with what was in the engine.

I would suggest you drain all the coolant completely, thoroughly flush the system with pressurized water and, if possible, flush the system in the REVERSE direction that water usually flows. I don't know about that particular engine but on an 8V71 it is difficult to get all the old coolant out using the drains that are easily accessable. So it's important to ensure that you get fresh water running through all parts of the engine.

After THOROUGH flushing, refill the system with coolant approved for the engine. I'd bet that will solve the problem.

Totally agreed. I have seen this exact thing happen. Take GM Dexcool and mix in some regular green stuff and you end up with brown/black goo. I say flush & fill...then monitor for further problems.

[robymayway]

I guess everyone has their own views but I would never put that stuff back into the engine, no matter how much I settled and filtered it.

Ok. that's my opinion too

[robymayway]

INCREDIBLE DAY....
I have drained the old coolant from motor on left side ( that run at 195°/197°) and 24 litres coolant go in a plastic tank but...surprise...5,8 kilos of sludge!!!!!
I have refilled fresh water seven times but some traces of sludge are still go out from drains!!!!
Tomorrow another couple of fresh clean water to finish.

I know what doing during the week end..!!!!!!!!!

[REBrueckner]

Boy that DOES sound like the problem....
Are you running the engines until warm, not hot, for circulation before each drain?? that will help flush out sludge more effectively.....you can always leave plain fresh water in there for a week or so....just don't drain while the engines aere at full temperature...and NEVER fill a hot engine with fresh liquid...

I recentlty posted my own coolant drain experience: When I switched from old heavy duty green coolant in my 1972 8V71TI's, I got no sludge whatsoever from my engines;Coolant was almost 11 years old but I had refreshed one gallon (half water, half antifreeze) annually during that period...the nitrite reading was bad this time via test strips, so I decided on a change.
A second refill with plain water and a drain after about ten minutes run to warm and circulate the fresh water appeared to remove the last of the old coolant....I was expecting something to come out with the old coolant, at least some crud, but it was surprisingly clear....

[robymayway]

I have spent all my week closed into engine room to flush and drain both coolant system engines. At the end all seemed to be perfect and ready to start. I refill with a new coolant antifreeze

When I go out to find the temperature, I notice that after 10 minutes at 16 knt, the temperature of engines was exactly the same before my cleaning job.

I gave a call to my mechanic and he supposed that problem could be the headexchanger that he cleaned last year with acid..

I really worried about...

[robymayway]

I have spent all my week closed into engine room to flush and drain both coolant system engines. At the end all seemed to be perfect and ready to start. I refill with a new coolant antifreeze

When I go out to find the temperature, I notice that after 10 minutes at 16 knt, the temperature of engines was exactly the same before my cleaning job.

I gave a call to my mechanic and he supposed that problem could be the headexchanger that he cleaned last year with acid..

I really worried about...

Please what do you think about??????? help me!

[Genesis]

The black crap had to come out but that's not the whole story - obviously.