Should I change the powersteering fluid?
 

Hello everyone. My 1997 E320 is a high mileage car, and I was thinking of changing the powersteering fluid + filter in it. Is this something MB recommends doing every 10 years or so, or should I leave it alone? By the way the steering works perfectly fine.

Do it. If there is a filter, then it was meant to be changed. Nothing could be hurt by changing to fresh fluid unless you did not put enough in or something like that.

If you have the time, the correct parts, you might as well. Beats having to mow the yard, or shovel snow (whichever your case may be).

Will the power steering system last the life of the car without maintenance?... perhaps. Wear particles develop in the system that can accelerate wear. Changing the fluid flushes away the debris, and hopefully prevent problems that can develop later. I don't recommend it for someone who needs to pay a mechanic to do it, but it's a good maintenance procedure for the DIYer.

Flush Power Steering Fluid

1. Lift front tires off the ground.
2. Disconnect the ps return line, drain ps reservoir.
3. Plug open connection at the reservoir.
4. Secure the return line to a generously-sized container (at least one gallon). If needed, add a length of hose.
5. Fill reservoir.
6. Line up your bottles of new fluid for quick pouring.
Here comes the fun part...
7. Have helper turn car on, and immediately have him go through full range of steering motion (left and right) and shut off car, all the while you are trying to keep the reservoir filled.
8. Button everything back up.
9. Clean up mess.
10. Top off fluid.

The front tires must be off the ground so the system is unloaded, otherwise the fluid comes out with a lot of force. The return line must be secured to prevent a big mess. Keep at least a gallon of ps fluid on hand. The helper must know what they are doing.

I prefer just to suck it out with a turkey baster several times. I try to do this about every 18-24 months... i also change the filter.... I use clear synthetic fluid... so I have a good idea when the system is dirty and what it takes to make it clean

No filter in his car.

I don't think you are going to get all the fluid out that way. Doing it the way descibed above flushes out the old fluid from the hoses and steering box. Of course, if you are using clear synthetic fluid you must know if you are mixing old and new. I just would not recommend doing it your way for anybody replacing regular fluid.

My Jeep had no PS Filter, and the pump died @ 171k (just like 3 months ago). Had I flushed the fluid it would probably have lasted longer. The pump was a PITA to replace but only $50. An MB pump... more $ so I'd flush it.

The turkey baster method is quick and easy, and is better than nothing. But I'm the type of person that refuses to do partial fluid changes on anything if I can do it better and refresh ALL the fluid.

On an older car...If it ain't broke - Don't fix it! :)

If you do want to change it anyway, I personally use the turkey baster method, until gradually the fluid becomes clear, after several changes. It gives me something to do, and to others, it looks like I know what I'm doing.

On a somewhat related topic: my '97 S420 has a plastic reservoir which looks like it came off an R170, not the round metal one that my S320 has. I googled for pictures of S420 engines and some have the metal one and some have the plastic. Any significance to this? Does the plastic one have a filter? I can't seem to locate one.

Oh, and I vote for the complete flush method. Its amazing what kind of gunk comes out of there!