I bought a used FX50s in June of last year. When I bought it, the power steering was loud in the morning and got worse as it got hot, but it was otherwise OK. I tracked the noise to the pump and swapped it out for a new one. I also swapped the PSF to Dex VI as it was a recommended 'upgrade' over the nissan PSF. It was nice and silent until a few thousand miles later when I stared doing some serious mountain driving. After it got hotter than normal, it would start to whine loudly. No performance issues, and when it cooled back down it would be quiet again. Initially I though the fluid level might be a little low and the G force from going around the sharp corners as fast as possible might have it sucking air. After adding a little more fluid and bringing it up to the hot line, the oil was starting to leak out of the cap. When I checked it while it was still hot, it was obviously aerated and expanding. I don't know how air could be getting into the system. The low pressure side is a straight line from the bottom of the bottle into the pump. I don't know if there is a different PSF that is less likely to foam, or if I need a larger PSF reservoir to allow the oil to settle. An additional cooler PSF cooler? It is totally fine until I am in really tight mountain roads and mid to high RPM. I suspect having aerated PSF is not ideal for any component in the system. I'm getting ready to head back into the mountains in a couple of weeks and am curious if there is anything I should do, aside from staying in a higher gear and or cornering less agressively.
A minor point is that this vehicle has electric rear wheel steering as well, and all the tires are a bit wider and stickier than stock - so steering gear load could be higher.
Is there a non-foaming additive? The oil I used was Mobil Dexron VI that was left over from the Buick.
Thanks!
A minor point is that this vehicle has electric rear wheel steering as well, and all the tires are a bit wider and stickier than stock - so steering gear load could be higher.
Is there a non-foaming additive? The oil I used was Mobil Dexron VI that was left over from the Buick.
Thanks!