Howdy all,

I'm going to backflush my OM617 in my 81 300D (84 engine/trans) tomorrow. Question: if I use a Prestone Flush Kit (or similar), it appears to me the hose to "cut into" would be the #4 hose in the link below to install the kit, yes?

Coolant Hoses - Mercedes-Benz Forum

My plan to do this is as follows:

1. Drain the system, including from the engine block, as shown in the iFixit below (my car only has expansion tank---no cap on radiator):

https://www.ifixit.com/Guide/How+to+change+Mercedes+W123+coolant/22768

2. Install the backflush kit; put in flushing fluid, fill w/water, run for 20 (until warm). Let cool.

3. Drain backflush garbage. Then run hose thru backflush kit until running clear. Drain.

4. Put 3 gal. distilled water in system; run for 20 (until warm). Let cool.

5. Drain again.

6. Fill system with antifreeze, properly mixed. Fini.