PeachParts Mercedes-Benz Forum - View Single Post - Mixing ATF and Power Steering Fluid in Steering System

Jeremy5848 · #15 05-11-2012, 05:21 PM

I would like to use Brian's method (and I have used it) but currently have two concerns:
(1) With the engine idling, fluid goes through so fast that it's almost impossible to keep the reservoir filled. I've though of clamping the return hose so that the fluid flow is reduced but that would create higher pressures in the system and I don't want to blow a seal somewhere.
(2) Some cars, like my '95 E300D, so carefully hide the return hose under the intake manifold that it pretty much requires pulling the manifold. This I don't want to do just to change fluid.

As to ATF vs. PS fluid, I suspect that the two are sufficiently similar that it's a moot point. When I drove GM iron, I used ATF in the PS circuit and never had a problem. OTOH, I use PS fluid in my Benzes because two of them have weak pumps (200,000 miles without ever changing the fluid didn't help) and I want to give them every chance I can to last a few more miles.

PS fluid isn't expensive so there's really not much reason not to use it unless ATF is all that's available in your particular situation. The important thing is to get the dirty fluid out and replaced by clean fluid that bears some family resemblance to PS fluid. One thing I have noticed is that it's easier to tell when the PS fluid is getting dirty if you use a colorless fluid (most ATFs are red). You may have to pop a few bottle caps to find a colorless PS fluid but they're out there.

Jeremy