Especially when I park for at least three or more hrs(especially mornings) and crank it up I get a light blue smoke coming from the tail pipe.I poured "emmission pass" additive and 'outlaw' in the gas tank but I still have the same problem.When it is warm there is no smoke from the pipe and not even when I rev it.
The car drives fine so far.I am wondering if I have a coolant leak in the chaambers but shouldn't I see coolant disappearing from the reservoir?I am not sure what to do other than to add Motor up oil additive which has been good to me in all cars.


90 LS400 with at 155k miles

 

You might want to check your actual exhaust and piping.
My car started smoking in the morning a while back then notice my exhaust getting louder several months later and then it falling off.
What is happening is that moisture is building up in your exhaust and then when you crank your car up in the morning it burns it.
My piping got to the point where the moisture rusted the piping and the exhaust just fell off.
This is what happened to my car and might be to yours also.
Just look for signs of rusting.
Good luck.

 

I only get white smoke once in a while,but it is natural to have white smoke come out during the winter right?when it is really cold.

 

I remember it failed emmsions last yr and the emmission guy gave me a break by bypassing that (he called it a transducer)round plastic thing that directely attaches to the EGR valve.I think this thing has arrows on it with three different hoses.I did replace it but this was before the smoking.I will have the mech. inspects the exhaust when he changes the outer and inner tie rod ends.
No check engine light either.

 

Yeah my engine light is on too,but the mech said the EGR vavle had some residue in there,but he said it will not hinder the enigne's performance.But i get a gassy smile from my exhuast even though it has no smoke or when it has smoke that smell is always there.The prevoius onwer never warmed up the car,therefore i have white smoke sometimes coming out,but only when it is really cold in the winter,like when you could see your breath turn into mist.The white smoke will only come out if i am at a complete stop with my engine on,if i a driving the smoke does not come out.

But i heard blueish smoke is even worse,there could be something wrong there,improper oil burning,or you might have a leak some where.

 

How much light blue smoke came out? a puff or a lot?
Could be the valve stem!!

 

Sounds suspiciously like valve stem guides. When they wear it allows oil to seep into the cylinders and causes blue smoke on start up. It will also cause you to burn some oil (not necessarily visable) in normal use.

Are you consuming oil?

 

I used motor-up in my stealth for about 5 yrs and the engine sounded much better than when I first got it.It used to have a noise in the engine but that went away five months after I used motor up.2 yrs after, my mechanic noticed my rear seal leaking (I think it is the seal behind the flywheel ).I am not ready to change out the clutch and so I havn't changed the seal either.
I did use motor up for the first time on the Lexus in Oct last yr.I think this additive caused the valve stems guides to either collapse a bit causing oil to leak into the chambers.What I may need to do is to put in an additve that will relax those seals around the valve stem.I hate to change 24/32 of them.I know there are additives for auto trannies and seal problems.Most engine additves like prolong,slick 50 etc... causes your rear seal to collapse.This is caused by hardening the seal rather than making it soft to be able to flex around openings.
If only I can find an additive that will stop this smoking on start up.
I definitely would not down motor up because it has done more good to me than harm.To me that will be the best oil out there besides the expensive Amsoil.No wonder the price for motor up has never fallen while all the rest have.