Bon

My new-to-me 2006 was low on power steering fluid when delivered. I topped it off and thought that was that. Wrong! The fluid was low twice again with no leaks showing. I did a little Internet searching and found that this is an issue that shows up in Toyota & Lexus vehicles, and has for about 2 decades!! Many power steering pump$ have been rebuilt and replaced in attempts to fix the disappearing fluid problem, of course, without success.

The problem is a small switch/actuator located on or near the power steering pump. Two vacuum lines attach to this switch. When the switches diaphragm develops a leak the PS fluid is sucked into the engine and burned up. Initially, the leak is small and the fluid amount is so small that little to no smoke is seen. Eventually the leak can grow and some white exhaust smoke is detected along with a "rich" smell at start up.

There seems to be some debate about why it exists and what it does but I believe it increases the idle speed of the engine when the power steering pressure drops. The increased idle speed spins the PS pump faster providing additional boost in parking lot maneuvers.

The device is mostly called a "vacuum valve". It is part number 17630-16040 and can be had for about $80, delivered. It can be replaced in 10 minutes if you have a thin 17 mm wrench.

Some have reported just capping off the vacuum lines and everything is okay. If you do this, be sure to cap off the vacuum switch ports as well because leaking PS fluid will drop down and destroy your alternator directly below the PS pump.

So, if you have to add power steering fluid but don't see anything on the garage floor think "vacuum valve".

scdroptop

iTrader: (1)

Bon-nice write up and thanks for the tip. Hopefully you can get it fixed. I actually had an entire PS rack go out (slow dying death) on my last infiniti fx35 and it caused the PS fluid to dramatically decrease with no signs of leakage too. Interesting...does the fluid just evaporate or get lost in the system?

Let us know if you take it to the dealer and if they fix it (you must still be under warranty) and if the fluid stays level.

Thanks!

Bon

The fluid is inhaled through the vacuum system of the car and is burned up in the combustion process. I'm waiting on my vacuum valve to arrive and then I'll replace it myself. If enough fluid is leaking you'll see white smoke from the exhaust. I'll follow up after things are sorted out and add anything else I learn in the process.

Dutchtater

I have the same problem with my lexus 400. I actually paid 900 dollars to get the pump replaced, but that didn't fix the problem. Instead I have to refill the powersteering at a daily basis now. So I get a lot of smoke! Hoping this will help. How did it turn out for you?

Bon

Well, things didn't go as I had expected. I got the valve on eBay for practically nothing. I went under the hood to replace the valve and began to snoop around looking at the steering rack. I noticed a single drip at the bottom of one of the inner tie rod boots. I loosened the boot and found that the boot was almost entirely filled with power steering fluid. The boot on the other side was also nearly filled with fluid as well. The seals of the steering rack were shot. The disappearing fluid had been simply leaking in the boots. I replace the rack with a rebuilt unit for about $350 and the problem was solved. I still have the vacuum valve as I watch the fluid level but so far it hasn't dropped.

scdroptop

iTrader: (1)

Bon-very interesting and sorry you had to replace the rack. At least you got a rebuilt one at a great price...I paid in the thousands for my FX35 rack when it went out so consider yourself lucky on that. Sounds like you are very handy...I'd be afraid to attempt this fix!