Puff of white...

R

Remarcable

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Live here in wi, just got a 2000 ls 3.9 130000 miles. Just started to get a bit of white smoke on one bank. It only happens on startup and goes away once engine idles down from warmup. Any comments would be appretiated. Next weekend I plan on doing compression test on all cylinder's and replacing cop's. Car has overheated twice and never got to read line on heat gauge I have a a bad degas bottle I'm assuming for I add coolant and it leaks out around front drivers tire. Just ordered the bottle will install as soon as it comes.
 
Are your 100% sure it is white... and maybe not actually having a tinge of blue color to it??? Puff of smoke on startup is usually the valve stem seals.
 
Could have been, it's ween cold out so it condenses pretty thick also. How can I inspect the valve stem seals outside of removing the head?
 
Stem seals are located inside the valve springs and up against the head. You have a bit of work to do since you must remove the cams in order to get at the valves. With the valves all shut in a cylinder, and a good seal against the seats, you can use an air pressure fitting in the spark plug hole to hold the valves shut while you remove the bucket and the valve locks. You can then remove the retainer and spring. And now you can get at the stem seal.

An alternative is to feed a length of cord into the spark plug hole and then 'bump' the piston up far enough that the cord 'bunch-up' keeps the valves from falling into the cylinder. I actually like that best, having done it both ways.

It is a lot of work but pulling the heads is un-necessary to replace stem seals.

KS
 
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I think that we are jumping rather far here. AFAIK, valve stem seals don't seem to be a problem point on the 3.9, unless he is maybe well over 300K miles (and he's not even close). It seems likely that his problem is something else.

Why don't we back up a little here. First, is it oil or is it steam (coolant) or is it rich mixture? I think that oil is most likely, but not necessarily from the valve stem seals. What do your tail pipes look like? Normal sooty, too clean, or oily?
 
It is easy to get away from the real core of a new thread. I absolutely agree with Joe. I don't remember stem seals ever being a topic of conversation here. They just don't seem to be a problem.

'White' would suggest water in the exhaust. 'Grey' or 'blue' would likely be the comment if it were truly oil causing the problem.

KS
 
Which after typing this... I should have asked you Remarcable... how your oil consumption is??? Either way,,, bad valve stem seals are not fatal to an engine... it just an indicator of engine wear. Either due to poor maintenance, cheap oil, or abuse.

Odd though... that it's just one bank of the engine.
 
Still unsure on color of smoke, it happened a handful of times and that's it. My pipes are clean, no oily residue, oil consumption is non existant. Well at least not a measurable ammount. And the comment on only one bank is actually what raised the question in my mind. Right now I'm just frustrated, suspension is making all sorts of noises and I just have a solid weekend of work ahead of me once parts arrive.
 
Carbon build up on valves prevents complete seal. Try removing Carbon deposits with Seafoam. Cautious not to hydro-lock it.
 
Valve stem seals won't cause much oil consumption, unless the valve guides are also bad.

Per chance,,, were you doing "short trip driving" where the engine wasn't fully warmed up... when you saw the "puff"? Or maybe was it in colder temps? Still doesn't exactly explain the one sided puff. Any loss of engine coolant from the reservoir tank/degas bottle?
 
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