My engines: 617.952 (300CD-T, Calif.).

Does anyone happen to know if M-B ever had a recommended interval for doing the citric acid/degreasing routine in a 617 engine's cooling system?

For years, I had thought that it was every three to four years when the coolant was replaced. However, somewhere (don't remember where) a while back I read someone's opinion that at this interval, doing so was unnecessary and a waste of resources.

Anybody have a definitive answer for this one?

Thanks-

It's a waste of time and resources unless the drained coolant has really been neglected.............a gallon of rusty coolant from the block drain would give you the clue.

Radiator flushes sometimes loosen stuff that later plugs Radiators.

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84 300D, 82 Volvo 244Gl Diesel

If you are talking about how to treat your car from new, then no, a citric flush is not needed if you perform the semiannual flush and refill recommended in the service manual.
if you are talking about repairing a neglected car that is having cooling system issues, it's best to start with a standard drain, and water flush, see if chunks of anything come out, and look for rust, or sediment in the block drain water. if this is found, then a citric flush may be warranted, but it can cause damage to a weak radiator/water pump, so prepare for more work if you start it...

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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!

Okay. Well, thanks for the insights.