Smoke????????

[gijoe]

I need help. I started my o1 v8 this evening and a big blue cloud of smoke came out, and my wife told me today that it has happened before once or twice in the year we have owned the car. Has anyone else had this problem, and if so what it turn out to be. To me is sounds like a fuel problem, but what? it does'nt happen all the time. Thanks in advance.

 

[SoonerLS]

Blue smoke is burning oil, which (normally) comes from one of three places:
1) upper valvetrain (seeping through the valve stem seals);
2) leaking past the rings;
3) blowing through the PCV and back through the intake.

It seems like burning oil only on startup is normally a sign of the upper valvetrain leak; unfortunately, I don't know the LS's plumbing well enough to say which one is most likely. It's possible that it comes from another hydraulic system, and is being picked up by the intake, but, again, I'm not familiar enough with the specifics of the LS to know if that's at all probable.

 

[2001LS8Sport]

There is one place you need to check ASAP! Since these cars have such a huge problem with valve cover seals leaking into the spark plug wells, that is one place that seems obvious. Now, as long as the spark plug is tight, it shouldn't be leaking into the combustion chamber. But these are aluminum heads! They expand and contract at different rates than the spark plugs. This can lead to a loose plug! If it's loose, the oil can seep into the combustion chamber when the car sits over night. This can be a very serious problem!! The 4.6 and 5.4 motors...and the V10's ALL have a serious problem with this. MANY come loose! To top it off, most those heads only have 4 threads holding the plug in. When it comes loose, compression can and DOES blow the plug right out of the head. When that happens, it requires a new head (or special insert installed) Lightnings are very prone to this...as have several Cobras. But in no way is this limited to supercharged applications. My wife's old '98 Expedition blew a plug out. My regular maintenance on my wife's Aviator and my Cobra now includes checking the plug torque every 6000 miles. (every other oil change) I have found loose plugs!! The oil in your combustion chamber may very well be from leaking through a loose plug.

I would pull my coil covers and coils and check for oil in the wells. Check your plug torque to see if anything is loose. Remember, it doesn't have to be very loose to let oil leak past the threads while sitting over night. If oil is present, reseal the valve covers.

 

[gijoe]

I do understand all that is said so far but the fact it does once in a blue moon and not on a consistent basis, that is what has me puzzled.

 

[lsbit]

I do understand all that is said so far but the fact it does once in a blue moon and not on a consistent basis, that is what has me puzzled.

Might not be oil. Could be a fuel injector sticking open intermittently too. Dumping gas into a cylinder can cause smoke on startup, and a lot of times people mess up on the color of it. It wouldn't hurt to make sure you don't have oil in your wells, and it isn't too hard of a job, but I wouldn't panic about it. Let us know what you find!