emopdx34

1993 Lexus ES300 has a power steering fluid leak (likely from radiator fan). I'm usually good at keeping the level up but sometimes forget. The car occasionally has a problem of running rough (idling, driving, accelerating...all of it). This seems to coincide with the power steering level being low. My question is, would a low level of P.S. fluid cause the car to run roughly? It's not the usual whine and groan that you hear when steering the car (I know that sound when I hear it), but it's an actual rough, vibrating under the hood like the engine is struggling. The problem comes and goes and, from what I can tell, is affected by the P.S. level. Is that possible or am I out of my mind?

LeX2K

Firstly, you need to repair the leak before you destroy the pump, if you have not already. I can think of two reasons low fluid would do that. One, the pump is putting heavy and inconsistent load on the engine, and two, there is a vacuum valve on the pump that is used to bring up the idle when the wheel is turned to compensate for load. With the fluid level low, the vacuum modulator is probably going all over the place, causing erratic idle.

nine3es

iTrader: (3)

i have a 93 also, same problem you describe. i had a pump leaking so i put on a new pump, it didnt leak for two days then all of a sudden it empty again. after some inspection i found the pressure hose that goes from the pump to the cooling fan was spewing fluid on the right bank exhaust manifold. there is an o2 sensor on the manifold with fluid drenching it, i thought that may have something to do with the rough idle but after reading Lexus2000 post, the vacuum valve is a more likely candidate.
when it happens to me, the engine spits and sputters and smokes like a mosquitto truck til i kill it and fill the reservoir, then its all good again for a while.
my hose will be here tuesday, hopefully that will end my leaks and rough idle.

ppericfe

Where did u get the ps hose??

jhenson

Does anyone know the name of this valve. I have read on a few other forums how this valve is a switch connected with the vacuum system and that when it fails it pumps ps fluid into the vacuum system. Not sure of the accuracy of that statement but the symptoms match mine. However I am unable to find any reference to the switch/valve in alldata or on any of the parts house websites.

any help would be greatly appreciated

CUMan

You may have been reading about a very common problem on the early to mid 90's LS models. They have a valve in the bottom of the PS pump which is supposed to increase or decrease the idle speed when the steering wheel is at certain positions. This valve is very prone to failure. When this happens, PS fluid is drawn into the intake manifold and is burned. This often creates a cloud of white smoke on startup, and it causes significant PS fluid loss.

This valve is not present in the ES models, to my knowledge. I know of no connection between the power steering and the intake manifold on these models.