Power steering fluid temp

morrisman1, Feb 21, 4:18am
We have had a bad run of power steering hoses lately, blew one in may last year, and replaced with another 2nd hand one, and that blew in January this year. The car is a pulsar, sr20ve, revving to 8500rpm. Running stock pulley on p/s pump.

I now have put on a proper 3000psi brand new p/s hose, but want to see whether the cause of the failures can be fixed. Today after 6 laps of qualifying I measured the temp in the reservoir and it was 120 degrees celsius. After measuring the temp in a couple road cars after a ten min drive its only 30 degrees, so its obvious that the race car is getting hot.

How hot is too hot? It runs basic dextron fluid. Could the temp be causing those hose failures? What would be the ideal temp for the fluid?

Thanks in advance

franc123, Feb 21, 4:26am
I'd be looking for excess pressure in the system, or else a restriction in the lines. You could always plumb in a small auto trans cooler in the return line and mount it in front of the radiator somewhere if it otherwise seems ok. You would hope it wouldn't be getting hotter than the mid 80's.

mechnificent, Feb 21, 4:54am
If the oil can handle it, the hose should. I doubt the revs make any difference because there is a pressure regulator. Those hoses should last for years.

I reckon you just had two old hoses.

mechnificent, Feb 21, 5:11am
Well, I just checked some specs and some industrial hoses are only good up to about 120c and a little more. I'd imagine automotive hoses might be better than that though given how close some of them get to exhausts. and still last for years.

Even the hose that is near it's temp limit should have a saftey margin, and be able to stand the temp for more than a few hours.

I'd still suspect old hoses.

m16d, Feb 21, 5:16am
Stick an air duct in to blow some cold air on the pump.

gmphil, Feb 21, 5:29am
my st182 celica has a factory 8mm I guess bundy style tube that run out in back in loop in front air cond radiator for powersteer cooling

sr2, Feb 21, 5:33am
I used to run a p/s temp gauge on our Cosevo race car, even with a small trans cooler on the return we would often run 115 to 130 deg with no problems. I'd look at fitting a new hose and don't forget to change fluid on a very regular basis.

mechnificent, Feb 21, 5:45am
And not all hydraulic hoses are the same spec.

petal_91, Feb 21, 5:50am
Don't race cars usually have manual racks? Convert it to manual ans get better road feedback.

bill-robinson, Feb 21, 6:08am
you must be older than me. was running PS in the 80.s on a rally car

morrisman1, Feb 21, 9:48am
running 9 degrees caster, it has enough feel with p/s! I drove it with no p/s once when the hose blew and it was a workout for sure and that was with only about 3 degrees caster at the time.

morrisman1, Jun 5, 4:54pm
I think Ill try the trans cooler on it, and see what the temps come back like. Id be surprised if a cooler dropped it more than about 50 degrees, and that would be close to ideal if the internet is to be believed! Its not hard to set it up anyway, the GTI models had coolers, just a basic tube in front of the radiator and ive got a couple of those setups there. No harm in trying I guess.

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