I've experienced similar issues with my fluid level in my power steering reservoir on my HydroBoost install as well.
Am running a PSC Power Steering Reservoir designed for HydroBoost install .
For HydroBoost it's recommended that the cap on the reservoir is vented.
I've been experiencing some PS fluid on the ground (underneath my car) . Seems that after retuning from driving( and things are hot), after parking in the garage overnight I am finding a small puddle of PS fluid. This is from the hot fluid expanding . A call to PSC tech support confirmed that only 2 things would contribute to this condition. (1) expanding fluid due to high temperatures & (2) fluid level too high.
I've switched over to a synthetic PS fluid which helps. I chose Sweet Mfg / Valvoline PS Fluid which is designed for racing and has a much higher boiling point so it's able to withstand higher temperatures .
In an effort to reduce PS fluid temperatures, I installed a De Rale frame rail mount style cooler on the lower edge of my rad support behind the grill.
I've also removed 2 oz of fluid from the reservoir which leaves plenty still, but now has the fluid 1/2" below the max fill line in the reservoir. They recommended their anti-splash / pressure relief valve, which reduces the likelihood of cavitation . Apparently it keeps the reservoir under slight pressure (6 psi) .It's a simple plug N play install....cost me $75 from Summitt Racing.
PSC Remote Anti-Splash Steering Fluid Vent with Pressure Relief Valve (ASV) <a href="http://www.pscmotorsports.com/motorsport-specific-products/offroad/reservoirs-overflow-bottles/vent-kits/remote-reservoir-vent-line-kit.html"_blank">Remote Reservoir V
www.pscmotorsports.com
One last thing I also did was add a small bottle (4 oz) of LubeGard Red PS fluid conditioner (keeping the fluid level below the max fill line still)
Maybe overkill, but I"m happy to report that my overflow conditions have disappeared now.
Here's a thread I posted on it recently on another board. Hope this information is helpful to you & others.
Installed a PSC Power Steering Fluid Reservoir last year on my HydroBoost install and has been working well since last year. However, just recently this summer on 2 occasions after driving in hot temperatures parked the car in the gargage and next morning found a puddle of power steering fluid...
turbobuick.com