My power steering overheated and spilled fluid in the engine bay at a track day today at Lime Rock. My instructor said "oh yeah, that's normal, I fill mine low to allow for expansion". What's making it get so hot? Higher RPM's means the pump is turning too fast? What should I do about this?
PS, the track day was GREAT! 
Teh Volvo does this sometimes too. Lots of steering load makes for hot fluid.
Get a cooler if you can, or a better one if you already have one. Your pump and rack will thank you.
If the system is puking fluid, it's getting too hot. Add a cooler to the return line and the problem will most likely go away.
I know Group B rally cars had PS coolers
My Neon puked because there was not enough height difference between the reservoir and the pump. It had the reservoir on the rear of the motor and the pump was high on the front. I switched the pump out to a cloud car pump that mounted the pump lower, under and behind the reservoir. Pumps don't like to suck and the pump inlet needs to be well flooded. If the pump has to suck at all it will cavitate and foam the fluid which then makes the reservoir over flow.
Never had any fluid puking after that, I even took off the heater core I was using for a cooler in an attempt to stop the puking on the old setup.
Alright, so most likely just adding a cooler will fix this. On my Datsun the reservoir sits on top of the pump. I didn't notice any foam at all - just hot fluid all over the engine bay. Thank you!
I have used the Lucas ps fluid to help with this in the past as well. Just topped it up after it puked and never had the problem again, maybe 25/ of the system was Lucas
Amsoil synthetic ATF is a good fluid if your system uses ATF - if it does, you're lucky you didn't have a huge fire when the fluid overflowed. ATF burns like napalm, water just annoys it.
The heat is built up both by higher pump RPMs and by using PS assist more heavily (which causes a lot of heating in autocross).
Here's the PS cooler I put on mine, a Hayden 401, costs like $20:
M3s are notorious for spewing PS fluid out the res at the track. There is a vent hole at the top of the cap. Some people ignore it. Some people put a sock on the top of the res to soak it up. Some people put a hose and catch can on the vent hole. The cars aren't notorious for killing PS pumps at the track like some types of Porsches, for example.
Some M3s spec ATF, some spec CHF 11s. Like everything else in an engine compartment, ATF or CHF 11s will ignite if a vapor spray of it comes into contact with a hot exhaust tube. The question with all this stuff is, HOW hot an exhaust tube. Most of the time it just cooks off without anything worse than a bit of a stench. But you never know what might happen.
My Fairmont would always puke fluid at the autocross, and it got so hot at its first track day that it melted the dipstick, then failed the pump. I keep a rag over the cap to catch any spray, and I added a cooler to the system to save the pump. Fluid temps were above 240° before, now they only get about 120°, running standard Type F. It still tries to blow fluid out at the autocross, but I'm pretty sure that's because it's not designed to steer that fast. It does the same thing if you steer the car, even very slowly, with the engine off.
rslifkin wrote: If the system is puking fluid, it's getting too hot. Add a cooler to the return line and the problem will most likely go away.
This. And/or using a super high temp p/s fluid. I switched the Forte to Amsoil (highest boiling point) and was good to go.
If you have a remote reservoir, aside from lowering fluid level a bit, you can often insulate it, or move it away from whatever is heating it, or both.
This is standard practice on the Solstice, which parks the reservoir right near a hot turbo...
Another possibility is that the pump is overspeeding at the rpm's seen on the track. We had this problem with Focus SVT's on the track. The problem was solved by changing the pulley size to keep the pump speed down.
Hal wrote: Another possibility is that the pump is overspeeding at the rpm's seen on the track. We had this problem with Focus SVT's on the track. The problem was solved by changing the pulley size to keep the pump speed down.
May we assume that the slower pump speed will also lower fluid temps?
Lower pump speed will lower fluid temps to some degree, but it will also reduce assist at lower RPMs. I'd recommend trying a big PS cooler before changing the pump pulley.
Had this problem on my 4th gen Camaro, killed the PS pump in one particularly warm weekend of auto x. I added a cooler (any old cheap tranny cooler should do) and replaced the pump with a Turn One unit and never had issues again.
GameboyRMH wrote: Lower pump speed will lower fluid temps to some degree, but it will also reduce assist at lower RPMs.
True, but we weren't worried about low rpm performance on this car.
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