kforbez88

I have a 1994 LS400 with 167k miles on it. I just had a recent issue with white smoke coming out the exhaust when it starts. Im hoping its the head gasket & not a crack in the engine. There is oil leaking out of the bottom... Have any of you owners had to deal with the same issue? If so, what were the results?

bradland

Luckily it's not the engine, it's the notorious power steering air control valve leaking fluid into vacuum lines. Those same vacuum lines allow the fluid to enter the intake only to be burned off during normal combustion which produces the white smoke you are seeing. Every LS400 ever made eventually does this and there are several ways to tackle the problem. Fluid leaking through the valve is not inherently bad, aside from forcing you to top off PS reservoir occasionally, but it does get worse. When this happens the fluid leaks outside the valve and drips down to your alternator ultimately killing it...

Here's a link to several threads on the topic-
https://www.google.com/search?safe=o....0.1qfebRY7c2Q

Moarpower

My car had the PS issue bit it had light levels of white smoke for longer than just ignition.

I have not had to deal with this in my LS but have had it in other used cars. Often a big cloud of smoke on ignition is indicative of clogged oil tracts and potential fuel build up due to a poor service history. I had a car that would never blow any smoke, unless Id drive it over 200kms and park it. The first ignition would blow a ton of smoke, then it wouldnt happen again.

Is the car running ok? It could likely just be too much fuel being dumped in for the ignition process. Its not hard to tell if you have a head gasket out.

PhilipMidd

Its probably going to be the ACV vacuum valve on the power steering pump. Dont feel bad, they ALL get this problem and its cheap to fix for good. Most remove the vacuum switch and just blank if off. If you follow the vacuum pipes that run from the front of the intake manifold down the RHS of the motor (passenger side if your in the US) you will see they go into a connector screwed into the base of the Power Steering Pump. That switch is not really necessary and can be removed and blanked, with the 2 vacuum lines either plugged or simply joined to each other at the manifold.
It looks like it needs to be replaced about every 5-10 years, or simply blanked off. If blanked, the difference in steering is almost imperceptible, but if its noticed, its only noticed at idle and when the engine is cold. I had to do mine as it was at the point when I purchased the car that every time you filled up with gas, you also had to top up the power steering fluid. No idea how the previous owner put up with that!
Its an easy fix, if a little awkward to get to. Easiest to get to it from underneath the car. You will need a short series 17mm spanner and disconnect the battery - its too easy to short out to the alternator if everything is still live... dont ask me how I know!