several months ago I flushed the cooling system on he 1984 300DT using the following method:

1. installed a prestone back flush kit, hooked up the garden hose and turned the hose and flushed long and hard. lots of gunk came out

2. closed off the prestone back flush kit, reattached the radiator hoses and closed off the drain plug. mixed shout ultra gel with warm water and poured into overflow tank. filled the cooling system with tap water. started car and ran for 20 minutes with the heater on full. drained. again, and lots of nasty crud came out.

3. repeated step #2

4. mixed Mercedes Citric flush per directions on label and performed the citric flush. more nasty looking stuff came out

5. drove the car for three days with just tap water in the cooling system. then, opened up the prestone backflush kit and ran the garden hose on full blast with the engine on and heater on for approx 20 minutes.

6. replaced almost all the cooling hoses with new gates hoses and a new Nissens radiator. installed Amsoil 750,000 mile rated coolant.

today, I changed out the top radiator hose because I had forgotten to do this. I noticed rusty looking stuff in the top of the new Nissens radiator as well as the connection to the top of the engine block. after the multiple flushes, it seems odd that there would be any signs of rust, what gives?

I'm thinking of a complete thorough flush like this again in two years......any thoughts or ideas concerning the rusty appearance are appreciated.....

If you run a car with tap water instead of coolant you are encouraging gunk and rust - Much like in a domestic water heating system you'll get gunk and rust for a bit until the oxygen finds its way out of the water (and gets bled off by you). I guess you've done a really good cleaning job by de-gunking but then allowed the tap water to attack the clean bits thus reintroducing rust again.

If I were you I'd change the coolant and see if it goes rusty again. It shouldn't do. Sorry I know this is expensive. May be put in cheap coolant first and then go for the good stuff?

need to clear up one fact. after the last flush, I drained and removed the old radiator and drained the engine block. after installing the new hoses, new radiator, I then refilled the car with a 50/50 mix of distilled water and Amsoil 750,000 mile coolant. nothing there that should cause rust.

I think I'm going to run the car as it is and reflush in two years.

when you flush again use a gallon of vinegar plus some water as the flush

drain radiator (I pull the whole thing out to drain plus get bugs out of fins)
and block drain (I know you did this but I'd mention for others)

You used distilled water thats good (great) most people use hose water and that's
got scale in it

you should be fine after this

side not... I pulled heads off a buddies ford wagon last week and at 98,000 miles

the scale in the water jackets was incredible crusty sheets like you would find in a coffee maker

no regular flushing and HOSE WATER!!

I'm not sure how it is on a W123 as I haven't owned one for that long but on other cars I've seen rust coming from water pumps. Is this a possibility?

I wouldn't run your car for another two years without keeping an extra special eye on the coolant. If it is already rusty in colour I guess some of it could settle in an unwanted place and cause you a different problem.

yeah, I guess you are correct. probably need to keep an eye on it. it just seemed like I did a lot of work flushing the car and I'm just surprised there is any rust at all.

but, as they say, there are no guarantees. and, the water pump question piques my interest.

Squeeze the heater/coolant/radiator hoses. Hear any crrrrunch?

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http://farm8.staticflickr.com/7271/7...144c3fc1dc.jpg

Hey HuskyMan,

I saw this and I thought of you! (great combination of words with your user name...)

http://www.peachparts.com/shopforum/diesel-discussion/279325-short-using-citric-flush-post2487705.html#post2487705

See post #2 - "If you must get crazy...Pull your H2O pump and inspect the Impeller..
Any Rust ? No, then you're Golden! (Usually the first sign of Corrosion is on
the Impeller.) "

Does anyone know if the Mercedes Citrus flush is anymore than granulated Citric Acid? Would there be any harm in just using food grade Citric Acid? Either way, the system has to be flushed vigorously and so it would seem that any differences would be nil as it all gets washed out anyway. Also, how much of that stuff is in one of those Mercedes brand bottles of Citrus flush?

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'82 240D 224K miles manual transmission
mods: wooden 4by4 bumper, EGR delete and older EX manifold without EGR port, glass pack muffler (cheapest replacement muffler), rebuilt bosch injectors with Monark nozzles

working on: aux electric fuel pump, coolant/fuel heat exchanger/filter head, afterglow, low oil pressure buzzer/LED

I believe that the only good way to get that decades accumulation of rust and junk from the bottom of the coolant jacket cavity is to take out the ' freeze plugs' and use a power washer with a 90 degree bend in it... while at the same time using a wet and dry vac to pull the water and junk out ..... so as to not allow water to build up and degrade the power washer nozzle effect...
This stuff naturally accumulates where the flow of coolant slows down or turns a corner... and after decades I do not believe you can address it with the simple and non violent methods yall have described.. or what the FSM says to do..
Most engines would have had a rebuild by the time they had existed as long as ours... and in the old days the standard operating procedure for doing a rebuild was to take everything off the block and Hot VAT it.. dip it into some nasty stuff which would clean out those recesses... then clean it and put it back together...
I have not heard of anyone doing that to any of our engines... and this stuff is as hard as concrete after a while....

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Citric Acic is just Citric Acid, nothing special as far as I know.

I bought a MB bottle of the stuff, it is granulated and I think it is in a one # container. have no idea where it is so I can confirm it.

I bought it to do the old engine, then the chain broke. took care of that project..

Citric Acid is sold on E-Bay, might want to check it out.

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works