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99 LS400
There's usually a bit of thin white smoke upon start up but it doesn't go on long.
After flushing and adding new coolant, the smoke has gotten a little thicker and it becomes even more thick when blasting the heat and the car is always operating slightly above normal temp.
Also, there's the original thermostat.
220,000 miles.
I think it's stuck closed because coolant isn't circulating properly.
Did a full flush to remove the green coolant that was previously used and when I removed a hose to get to the thermostat housing, green coolant spewed out of the engine and red and green mixed coolant came out of the hose.
problem here is, bottom nut to housing is stripped clean and I cannot get it off in any way.
was going to change the thermostat to see if it helped any of my issues.
None of my fluids are mixing.
could it just be the pesty t stat not circulating coolant properly and causing the car to run above normal temp?
Sounds like typical head gasket issues. Pressure thest the cooling system and start from there. If gasket issue is onfirmed
the sooner you fix it it'd be better. MAY COST SOME $$.
As long as it only happens at start up it's more than likely the ACV on the bottom of the power steering pump leaking fluid into the vacuum hoses attached to it. The ACV (air control valve) is designed to open when the PS pump is under load allowing air to circulate through the vacuum lines eventually entering the intake which increases rpm's slightly. This slight increase in rpm speeds up the PS pump which makes the steering wheel turn with less effort. Take a look at the bottom of your PS pump. As long as the valve isn't leaking fluid externally, which will drip on the alternator, it's not necessarily a priority repair. Every LS400 eventually does this...
Hard situation for sure. Power Steering has a vacuum boost that commonly leaks into the intake causing smoke from the tail pipe. Honestly, thermostats going bad are quite rare in modern times, so be it possible it isn't the first thing to replace anymore. Put your hand around the hose from the thermostat, does it get hot and you can feel the coolant surging through it if you squeeze it? Watch out for the belt and fan though. How about the bottom hose, Is it hot? https://www.google.com/search?q=how+...-b-1#kpvalbx=1
Disconnect these 2 vacuum hoses and see if you still get white smoke. It may run a little rough during the test but focus on the smoke. If it stops a leaky ACV is the culprit...
How often do you need to top up your power steering fluid?
When the ACV is leaking really badly (like mine was), you have to top it up about as often as you fill the car with Petrol (Gas for all you Americans out there).
This was the issue with mine when I purchased it. Big clouds of white smoke when starting, but I didn't notice any when running - but then I wasn't really looking for it when running. At first I assumed bad valve stem seals and had decided not to worry about it. After joining this group and looking at a heap of posts I come to realise that it was likely to be a bad ACV. And it was.
Very easy test. Just pull the 2 lines from the manifold going to the power steering (shown in Bradland's image above). Temporarily plug the 2 manifold pipe connections you just disconnected and secure the lines someplace on top the engine (just stop them from flopping around and maybe getting tangled in the fan or whatever). Take it for a run. Any smoke while running? But the main way you will see is the next day (or after the car has cooled down and been left long enough for PS fluid to leak out and collect in the vacuum lines). You will know instantly on the next start if its the problem. No white smoke on startup. Also check to see if any PS fluid (it should be red) has collected in either of the 2 tubes. Its red not semi-clear because its actually AFT Dextron III - or should be. The PS does strange things when people put PS fluid in it. it NEEDS to be ATF as stated in the Owners manual.
The ACV (17630 above) only last about 10 years or so. So most have been replaced at least once by this age. Most people now just remove it and plug it. 14mm X 1.5 if I remember correctly. Less than 15mm long or it may fowl something in the PS Pump. Then Plug or join the 2 vacuum connections atop the motor.
Hope this helps.
Guess that just leaves the blown or leaky gaskets. 😓
If a head gasket, then you are going to have more than just a little white smoke...
Losing coolant or oil discoloration?
Inspect your spark plugs if that is a concern.
Had very slight wisp of white.on start-up and problem resolved by changing steering pump ACV...20+ rubber o-rings are brittle and do not seal.very well..others have plugged theirs, but like the idle up feature and steerimg feel.when parrallel parking.
Also consider your fuel injectors are not holding pressure and dripping into combustion chamber after shutdown.
Last...remove throttle body and inspect bottom of intake manifold for pooling of any liquids...
Not losing any coolant, not enough to need to add any.
Oil is normal.
No mixing of fluids.
But my exhaust has the dreaded sweet smell.
Seems as if my lower radiator hose isn't running as hot as my upper radiator hose.
Upper being too hot to touch while the lower is just a bit warm.
My fan clutch is bad, definitely not running properly, bit of a wobble and it keep saying coming loose and one of the nuts to my thermostat housing is stripped clean so I'm having trouble getting in there to change the thermostat.
Seems as if my lower radiator hose isn't running as hot as my upper radiator hose.
Upper being too hot to touch while the lower is just a bit warm.[/left]
That means your radiator is working as advertised.
Just had this same issue... Its likely the ACV Valve which has leaked fluid & destroyed the vacuum hoses. Took mines to the Lexus dealership, cost was $280. I would check out your power steering pump also, you mines well replace it while you are under it.
08-01-18, 06:07 AM
White smoke from exhaust.
