LS4001UZPW

Hey guys. New to the forum here. Just picked up a 90 LS400. Previous owner was dishonest and never told me the white smoke on startup. He drove to me for me to look at the car. Anyways...
The car has no leaks. The floor is spotless where it's parked. When I start the car from cold, the car blows real white smoke for about 10 seconds then clears up. Smoke is not real thick. No funny idle and no weird noises. It doesn't really have any distinct odor aside from the gasoline. Not bluish or yellowish or anything like that. When I bought it, the car had low power steering fluid. I put some power steering fluid with stop leak(didn't know bout dextron II ATF until after). And now it seems the fluid has gone almost empty as the whining noise is back.

So since the fluid has disappeared somewhere but not leaked outside, I am assuming it going in the ACV as some others have indicated. Just wanting to see if that would be the case since fluid is not leaking outside. I also put fresh oil in it as it was due for a change. Previous oil wasn't dry. If it is the acv, should I go about plugging the ACV first? Lemme know your thoughts guys. Thanks a bunch and glad to be a Lexus owner.

RA010623

iTrader: (1)

it could be just moisture in the exhaust.

trukn1

LS's are notorious for this problem. What you have is a leaking PS reservior, specifically the Idle Air control valve. This is allowing PS fluid to seek into the combustion chamber, and being burned off on startup. The white smoke is the indicator. This is/was a fairly common problem. Please refer to the "Power Steering bible" in the stickied section, and it will explain more in detail as well as the fix. this is located in the FAQ (frequently asked questions for UCF10(89-94).
https://www.clublexus.com/forums/ls4...ls400-faq.html

www.lexls.com is also another great source of info on these cars.

Posting the same info in multiple forums is known as spamming, and it is why the post was moved here. I cleaned this up a bit so that your thread directly addresses your problem.


Welcome to the forum!

LS4001UZPW

Well it happens every time on a cold start, hence I kinda ruled that issue out.

I think you hit the nail. Thanks alot for that piece of info! I'll follow that.
BTW, so do I have to replace the PS reservoir? Or if I just cap off the Idle Air control valve and that should do it?

P.S. thanks for putting this on the proper section. I didnt want to post on 2 forums. When I initially posted it appeared on the detailing thread. So I created another one on the LS400 section which is where i wanted it to be. So thanks alot and didnt mean to 'spam'. =)

P.P.S. Gonna have the car washed over the weekend so I'll post some pics =)~

Yamae

Judging from the time length, it could be the valve stem oil seals not in very good shape any more. Aged cars tend to have this problem. The best solution would be to replace them all. But you could neglect it if it were within 10 seconds.

trukn1

No problem with the help,,, is what myself, as well as many others are here for. Complete replacement of the reservior is not necessary. You can just replace the valve itself OR cap it off (see the links I provided to aid in doing so). Capping it off will make a SMALL difference in the Power steering feel, but hardly any to complain about. Also check the lines leading into the reservior from the underside, as they are probably cracked and in need of replace. Fixing the PS leak has ALL KINDS of positives. Biggest is that it SAVES your alternator, which sits directly UNDER the reservior and WILL DIE (eventually) from the fluid being leaked inside of it. Changing out an alternator is not a hard job,, but it WILL be a PITA to do if you haven't done one on these cars.

This is also a good response, as older Toyotas ALWAYS had this problem. On the LS, particularly the first gen as being discussed here, this car was probably the most OVER ENGINEERED car that Lexus ever did. White smoke on start, has ALWAYS been the sign of leaky PS system under the reservior. BLUE smoke out the exhaust would be more indicative of the symptom you describe, as that indicates oil being burned off. Such is the case with older Toyota's

LS4001UZPW

Thanks for both of your response. That's why I smelled and observed the color of the smoke when it came out. It's white, very light, and doesn't have the smell of burning oil at all. Anyways, I'll start off with the power steering and the idle air control valve. Pretty sure that's it. Thanks alot.

steve2006

It's the power steering air valve mounted on the body of the PS pump that needs either replacing or blanking off not the IACV which is located at the front of the intake plenum chamber.

The valve looks as below.

LS4001UZPW

I assume you mean the Valve port as indicated in the picture below?

j2b4o

Standing in front of the car look down the right side of the PS pump and you should see it. If not just reach your hand down there and you will feel it. Or just follow the vaccum lines that run down there. New they seem to run around 95$ in NY, I capped mine untill I have 100$ I feel like wasting. Had the same symptom but very little smoke for like a second.

steve2006

Yes that's where it fits.

LS4001UZPW

I'm about to work on it this weekend. I assume that the air valve is attached on that port?

Also anyone know what plug size is for the valve port to be blocked? I read it's "14 x 1.5"? Can I find that in Lowes or Home Depot? Reason I ask is cuz I'd like to have it beforehand instead of taking the air valve after unmounting everything then having to go to the store.

LS4001UZPW

Well seems like problem is solved for now. No more white smoke. Instead of going under and taking off the steering valve sensor, I just unplugged the two vacuum lines and capped those and plugged the valves on the intake. Seems to be working for now. Thanks to everyone for their input. Really appreciate it,

fixmiester

Not quite sure what you mean by that. If you didn't fully plug both ports on the valve body, you will probably start seeing PS fluid dripping down from your alternator. It's the diaphragm in the valve body that is leaking into the intake manifold that caused your oil burning problem, and that is still leaking, so those ports must be sealed really well, to avoid dripping now.