Power Steering Cooling

[92saturnsl2]

On pretty much every vehicle I can remember working on, I've noticed the power steering always has a metal line that creates a long loop that the fluid must travel somewhere. All my vehicles have it, one is on front of the A/C condenser, my truck has it tucked into the front crossmember, they always seems placed were it will receive a lot of airflow. I assume this is for cooling purposes, but why? The only time it receives a good amount of airflow is presumably when you are driving straight ahead at speed, where the PS is not doing much. Does this long loop serve some other purpose? Just a curiosity question...

 

[Lolvoguy]

Any speed faster than walking speed will cool the PS fluid in the loop.
That's the purpose of the cooling line. To reduce the rate at which the fluid breaks down.

 

[Chris142]

My Ford routs it along the frame making the frame a heat sink.

 

[GZRider]

PV=NRT Power steering fluid can be under very high pressure, it doesn't take a large amount of airflow to cool it.

 

[Skippy722]

My Durango had a dedicated cooler for the power steering. It was mounted down low in front of the AC condenser.

 

[Lou_Boyle]

The loop is indeed an oil cooler. As noted above, some vehicles will have a small finned cooler in front of the radiator as an alternative to the long loop.

The power steering pump is a positive displacement oil pump so the PS fluid is constantly circulating whenever the engine is running, even if you aren't "steering". The turbulence from the fluid circulation plus friction of the moving parts inside the pump is constantly adding a small amount of heat to the PS fluid. Without some type of cooler the fluid temperature would keep increasing until all the power steering components got hot enough to dissipate the heat being added - which might too hot for seals and rubber hoses.

 

[dlundblad]

Any sort of fan should help cooling if it's in line with the condenser and radiator.

 

[eljefino]

I had a car-- think it was my 97 taurus-- where the PS cooling fins were little knife blades. They may have started life slightly more blunt but the sand blasting of being under there really polished them into an inline row of scalpels.

92 bonneville put the cooler somewhere dumb, rear-ish on the passenger side. It rusted out and I replaced it with a small length of brake line, to no ill effect. I think the cooler is for when people are parallel parking (and not getting it right the first time) or driving the Mt Washington Auto road. If I had to replace it now I think I'd get some chintzy ATF cooler from ebay.

 

[Slick17601]

Originally Posted by Skippy722
My Durango had a dedicated cooler for the power steering. It was mounted down low in front of the AC condenser.


Did your Durango also have the fan driven by the power steering pump?

 

[cjolson140]

Not sure how the lines were routed, but my old Volvo 850 could have used more PS cooling. Five minutes of driving on a tight course would cause the PS to fail and burp a pint or more of fluid onto the ground.

 

[CR94]

Originally Posted by GZRider
PV=NRT Power steering fluid can be under very high pressure, it doesn't take a large amount of airflow to cool it.
?? PV=nRT applies to gases, not liquids.