Ls 400 Power Steering

Ian Lord · January 31, 2009

I have a 1990 - 173,000 mile LS 400, (Love it had it 7 years) I have had little need to use the car in recent months.

I last used the car 3 weeks ago on a 100 mile trip, 2 days ago I started up in the garage only to find that shortly after start up there was pink fluid loss on to the garage floor, seemed to come from under the front bumper /spoiler.. as nice straight line on floor.

Today I had a check and there was no loss of auto tranmission fuid, or break fluid, so it had to be Steering.. I checked the PS fluid level and it was down, also the fluid had gone a watery pink colour rather than the clear red colour it normally is..

My time was limited but there did NOT appear to be any leaks from the PS fluid reservoir, and as there is a large floor pan bolted to the underside of the engine compartment it is not easy to see where its coming from.. I would guess pipe work or steering rack? which could explain VERY small loss of Power Steering fluid, over last few years.

I gave the car a short run approx 2 miles, and the power steering still works, but on return to garage there were some strange noises from the power steering unit, I would guess because of low fluid etc.

* How can I confirm what the problem is?

* Is this common problem to LS400's?

Additionally I have recently ecountered lumpy running / miss firing / on some cylinders plus smoke and smell of unburned fuel

from exhaust, before this it never missed a beat since I owned the car, and always ran so smooth and quietly.

Would really appreciate some feedback from the "wise men" of the Lexus owners club

Regards

IAN

ROYT · January 31, 2009

Usually it is the PS pump.

Often this is only an 'O' ring failure where the reservoir joins to the pump body.

Plenty of info on this if you search LOC etc.

Popular fault, not usually serious!

Re smoke, possible plugs or HT leads, damp in it all if not being used etc.........

lss123 · February 1, 2009

Hi there had the same issue with my LS a year ago (Power Steering fluid shooting out of the front spoiler/bumper)

My brother diagosed this for me.

There is a U shaped powersteering cooler pipe running horizontally at the bottom of the radiator behind the bumper, this had corroded badly and had a tiny pin hole leak where there power steering fluid was shooting out from.

May be worth checking.

I got a replacement from eBay when someone was breaking an LS.

tigran · February 1, 2009

Got the same problem with mine - will change the o-ring between reservoir and pump this week and see if it fixes it. As a side note - all the smoking that mine does correlates directly to whether the reservoir has any fluid in it or not. So currently driving about with minimum PAS fluid as with a full reservoir it looks like a Trotter-mobile.

PAS seems like a common problem with the LS'

ROYT · February 1, 2009

Re smoke related to PS fluid, I'm sure i saw something on the US LOC about a faulty valve under? or related to

the PS pump.

Worth trawling the US site, they had the answer...

steve2006 · February 1, 2009

Re smoke related to PS fluid, I'm sure i saw something on the US LOC about a faulty valve under? or related to
the PS pump.

Worth trawling the US site, they had the answer...

ROYT is correct there is a black valve on the PS pump which has pipes connected to the intake manifold it is supposed to alter the amount of power steering assistance dependant on the road speed.

Many people have removed the valve and plugged the hole with a suitable threaded bolt ( loctited) and then plugged the vacuum pipes you take of the valve.

Apparently it make little difference to the power steering.

The reason why the engine smokes is the faulty valve allows PS fluid to be drawn into the intake manifold where is is consequently burnt in the engine and produces the smoke.

You used to get a similar effect ( for fun) when you poured Redex down the carb with the engine running and then took it out on the road ( this was age related fun when the police didn't have cars to chase you only push bikes that couldn't!)

Here's a picture http://i39.photobucket.com/albums/e191/ste...06/lexus006.jpg