Greetings Forumites,
I'll be doing cooling system PM service on the fleet ('84 300D, '83 300TD) in the near future and need to know what is safe to use for flush and fill and what is not.

All hoses will be replaced on these two vehicles at this time and the obvious thing to do then is a proper flush and fill. The message that I get is anything other than MB coolant will kill my radiators.

What should I use for a flush?
What should I use for replacement coolant?
Is there any other maintenance that I should be thinking about doing?

Best wishes to all. Without this forum, I wouldn't be the hero that I am to SWMBO and her 300D! And, I wouldn't own TWO of the finest vehicles ever built.

Cheers,
Randy Leo


Marlene- 1983 300TD; 221,123 miles and still cookin'

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First is a citric acid flush then a dish washing soap flush.

I go with MB coolant but this subject to very spirited debate.

Sixto
91 300SE
87 300SDL
83 300SD

Make that two de-oiling flushes (5% mildly alkaline solution) then a citric acid flush (10% solution). Completely flush with water between flushes.

Sixto
91 300SE
87 300SDL
83 300SD

There's also Redline Water Wetter and minimal coolant, no more than 25% I think. You can run Water Wetter with a 50-50 mix but the benefits of Water Wetter go out the window when there's a lot of coolant... or so says Redline.

Sixto
91 300SE
87 300SDL
83 300SD

Sixto,
This may sound crazy but, are there over-the-counter alkaline and acid flushes available or do you have to brew your own?

Any particular brands that you've had success with?

It ain't right but, I ran my last car over 130,000 miles and never bothered to flush the cooling system. Never had any problems either.

I despised working on that car and consequently, I did as little as humanly possible to it...


Thx for your help,
R

Try the dealer for citric acid. The part number is 000 989 10 25. I've never used it. I don't know if it comes with mixing instructions. The manual says 100g/l.

I've read of folks using dishwashing soap as a de-oiler. I doubt there's anything in dishwashing soap that's harmfull to the innards of a 617 even at full strength.

I've only used 2-3 flushes with tap water. It comes out clean enough that I don't feel the need to do more.

Sixto
91 300SE
87 300SDL
83 300SD

Hey Randy,

Off-topic here for a moment: You have the same color wagon as I do - it's only the second time I've seen one! Seems pretty rare...

Anyway, how's you're paint holding up on the hood and roof? I have a feeling that the maroon paint 'gives up' quicker than some other colors.

Joe,
Sorry to dissapoint you but that paint looks that good because it's only about 2 years old. I don't know the exact age of the paint because I've only been with Marlene about a month now.

Whoever had it done must have paid a mint for the job because it is absolutely one of the best repaint jobs I've ever seen on a car.

She was originally maroon so the fender wells and doors all match. And, other than some old seat problems and the carpet fading in the back, she's in great shape.

I'm really worried about fading too...so, I'm in the process of clearing out my garage and making a place for Marlene and SWMBOs 300D.

Cheers!
RL

I agree about using the MB citric acid flush. Be careful though, it is VERY CAUSTIC! DO NOT get any on your skin!! Buy a jar of the powder from the MB dealer and it will last you years. Then flush the system out with clean water and refill with 50/50 MB coolant and water.

__________________
Regards,
Aaron

Sixto, Aaron,
Thanks for all the information. I knew I could count on you guys.

R

it says use a 10% solution of citric acid (100g/l) in the service manual (20-015 under the engine section on the CD) to flush it out. I used it and used only 5% and it still did pretty darn good

__________________
2005 Audi A4 1.8T CVT -Silver/Black "Siegfried"

1982 300D - Silver/Blue "Ralph" -For Sale:
http://www.peachparts.com/shopforum/showthread.php?p=852260

1989 VW Diesel Jetta Blue/Blue "Bodo" RIP