LS400 POWER STEERING FLUID & EXHAUST SMOKE COMBINATION
Here was my problem the car is a LS400 1990
Morning start up, the car would smoke, white smoke, only at the start up. Also the Power steering fluid was going down even though it was not leaking.
How to solve this problem?
By the back of the power steering pump, behind the fluid reservoir, has a little vacumm valve that has two little hose coming in to the (Throtle Body/Intake Manifold) The function of this valve is to rev the engine up, in case of you turning the steering too much to one side , and having the A/C on, it will keep the engine from running RPMs too low.
To test and make sure that you could have the same problem, umplug the two little hoses from the (Throtle Body/Intake manifold) and buy two,litle caps and plug the two little niples where the hose where attached to the manifold. Drive for few days , and keep an eye on the fluid level and the start up in the morning. If the smoke is gone and the fluid in no longer going down, you will need to replace the little valve. I replaced my one by myself, it is quite a job, but I manged to do it. Also it is a good time to flush the system and replace the fluid. (MAKE SURE YOU PROTECT THE ALTERNATOR DOWN BELOW) If you have any question feel free to contact me . Good luck. MAY THE FORCE BE WITH YOU welgaby@msn.com

Thanks for sharing this fix with us.

Can this be moved into the workshop area?

Sure,
Anything to help fellow Lexusers like myself

mig25, thank you so much for this information. I have exactly the same problem. I have atleast 2 bottles of power steering fluid in my trunck. I have packed the car for hours and checked to see if i will see fluid on the floor to be sure i have a hole somewhere but not one drop on the floor.
Question, where did u get this valve from and do u have any pics of the location or items needed. I want to see if i can do this on my own

Thanks.

I hate to admit it, particularly when its cold, I love looking in the rear mirror, it's like the votex from a Concorde taking off. I also will check this valve if I can locate it.

What I find amazing is how did you discover where the fault was in the first place ?.

I too want to know

and me!

Created an account just to reply to this thread! Hopefully the info will be useful to someone.

We have a customer's vehicle here ('93 LS400) that has both issues (smoking and power steering fluid loss). This particular one has had the P.S. pump replaced by other shops three times already in an effort to remedy its persistent leak, but apparently nobody else that had worked on it knew to check that valve.


By the way, the valve in question is not the idle speed control valve as the O.P. had described. Toyota lists it as an "idle-up" valve, but this particular part does not regulate the engine's idle speed. The valve that does that (the ISC itself) is actually on the side of the throttle body.

What it really does is sample manifold vacuum and use that to command the pump to boost the steering fluid pressure as vacuum increases, so as to give more responsive steering at higher speeds. The problem is that when it fails internally the fluid passing past it on the pump side gets sucked into the intake, simultaneously creating both the smoking and P.S. fluid loss problems. (Worse, if you inhale enough fluid into the intake there's always the risk of a hydrolock and corresponding engine damage.)


The part shows on our copy of Mitchell OnDemand as costing about $200 (dealer list), the dealer I called showed it as about $100 list, and there's no labor entry for it but given its location expect to have to pay slightly above pump R&R time (which runs about 3 hours for the '93 LS400) to have it replaced if you're not mechanically inclined enough to do so yourself. It's not available though aftermarket channels so you'll need to hit up your Lexus dealer for it.


Hope all of this helps in some manner!

reated an account just to reply to this thread! Hopefully the info will be useful to someone. biggrin.gif



Created an account just to reply to this thread!
Hopefully the info will be useful to someone. biggrin.gif

I signed up to thank mig25 and HoneckerAuto, and to confirm!
I woulde like to thank you mig25 and HoneckerAuto for the information.

I just had an opportunity to buy 1991 LEXUS LS 400 wiyth the heavy smoke comming from the exhaust, loss of power stearing fluid, and really wrestling with the stering wheel. CAUSE NO POWER stering the CAR WAS UNDRIVABLE.

I bought it for almost nothing as the owner was scared to fix the engine and the power stering at the quote given him by the dealership.

I took the chance, and I won.
The car has it all on, and after repair of that stupid valve performs like new.

Full luxus at one month salary!


Just to confirm that the valve in question is LEXUS Part number 17630-16040, US LIST PRICE U$ 122.46, DEALER COST U$ 91.86.

The perts salesman called it "air valve".

After replacing it car is better that any BRAND NEW wheels.

All you need is a "skinny" 17 mm wrench.
The replacement with all the preparation took me about 10 minutes!

You access it from the under your car.

The wrenches are to thick, so you need a "skinny" one.

I disconnected both houses before replacement.
I plugged the houses with the 6n mmm bolt.

Than with the electrical tape sealed the intake manifold and other "throtle in" to which were connected the hoses.

The first cold start in the morning resulted in NO smoke!

At trhis moment I knew that is the end of the problem.

That trick make me at least 5,000 U$ !

Count SAS

You could buy the Vacuum Switching Valve for about 93.00 US dollars at www.irontoad.com , but remember that shipping into your countries will be a bit more than the 15.00 US dollars in the US and territories. There is also a tutorial on how to plug the valve and not worry about it. www.lexls.com and in the US Lexus forums. I sent for a new one, keep the PS tank repleshish checking it about once or twice a week until you plug or replace. The people that have plug it felt no difference. CPR