I have read the threads on it, but am still unclear. First off, are there any photos of exactly which hose needs to be disconnected (my car is a 1991 350SD).

The part I don't get, and I'm probably making it too complicated is that when you disconnect the hose from the resevoir, isn't anything you pour into it just going to go out through the opening?

How do you run and flush the system with basically a hole in the resevoir where the new fluid would go through rather than circulate the system.

Again, I know it's me, but I'm not getting it.

I just shypon what is in there out to a very low level and add to full and turn wheel a few times. Do it a few times. Get a quart or two of fluid. It will freshen up.

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1982 300SD

I've spoken to a few people and have convinced myself that by doing that, I am keeping the majority of the sludge in the system.

I'd like to do a thorough flush

And you have convinced yourself of the proper result of just changing the reservoir.

When you remove the return hose, you plug the nipple that you removed it from so that you can fill the reservoir during the flushing procedure.

I have written the procedure at least several dozen times on this forum and I may very well have left out the plugging of the hole on some iterations of the description.

I did this a bit ago, use a helper. I used a turkey baster (garage only!) to remove as much fluid as I could, leave the filter in place for now. Take off the hose where I'm pointing, plug that up. Stick the end of the hose in an empty container. Fill up with fluid, have helper start engine, it will pump the fluid out quickly, keep the reservoir topped up!
Do this for as long as you think you need to, to flush the system.
NOTE: when your helper shuts the engine down, you'll get a bit of fluid spit at you, have the cap in place. Hook that hose back to the clamp, swap filters, top off, start engine, have helper turn wheel from stop to stop, keep doing this until all the air bubbles are gone. Hold cap on reservoir, shut off the engine. Install cap. Good luck.

Attached Thumbnails

 

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83 SD

84 CD

Larry -

I know it probably gets old posting the same thing over and over again, but I'd really like to see your write up. ANd if there are any pics of the right hose, that would be good.

Thanks

See the attached thumbnail in post #5.

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83 SD

84 CD

Sorry - somehow I managed to miss that. i appreciate it. The garages all want around $100 to do that -- pretty ridiculous.

^ No prob, agreed $100 is too much.

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83 SD

84 CD

Finally got around to getting it done. I had previously used the procedure on the dieselgiant site. But all they did was recommend a filter change and changing the fluid in the resevoir. I changed the fluid and the filter, then started it back up and saw that the fluid was dirty again. So I changed the fluid again and re-started. Instantly dirty again.

I knew that was a bad process and that's why I wanted to do the flush. Unfortunately, I burned an expensive filter and a liter of Mercedes PS fluid to find that out.

When I did it the right way, I ran it and the fluid was still nice and clean.

That is some nasty stuff in there. Anyone just changing out the fluid should think about doing a real flush. The nasty stuff just stays inside the system otherwise.

Thanks for all the help.

toomany MBz post had all the necessary information PLUS a picture.

There was no need to replace the filter the second time. Since you flushed it thoroughly and got fresh fluid in, the first filter you replaced would have done the job for many Moons.

There are indeed some folks who believe that changing the filter and the reservoir change will do the job. As you found out, they are fooling themselves. Same thing with brakes. The nasty stuff is down in the system. Changing the reservoir does hardly anything more than doing nothing at all.