Smoke from the Tail pipe??
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Smoke from the Tail pipe??
My 4.2 has 123,000 miles on it and today i noticed that when i started it a big grey puff of smoke came out of the tail pipe, shut it off and tried it again and now its fine. should I be concerend ? any ideas? is an oil additive something to think about?
Lead Driver
Joined: Sep 2006
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That usually indicates excess oil is being drawn into the combustion chambers along with the air and fuel injected.
The oil often is from wear around the intake valve stems, guides and the seals around the stems are hard and no longer provide a seal around the valve stems.
This is all subject to intake vacuum when the cylinder is on the intake stroke and pulls the oil in with the air and fuel.
When the engine is shut down hot, the oil is thin and runs down the stems from the head area above into the stem head area and is exposed to the intake vacuum when it is the highest except on decelleration it goes higher yet and you lose oil and don't see it while driving..
You might get some relief from an oil containing a softener but don't rely on it.
Effects of wear and age cannot be reversed with additives.
Exhaust smoke relitive color usually tells what is being drawn in.
Black usually is excess fuel but can be oil as well.
Grey usually is oil.
White is often anti freeze or transmission fluid.
The make up of the oil also has some effect on the color when passing through combustion.
Only way to clear your issue is replacement of stem seals as long as the valve stems and guides are not worn excessively.
Good luck.
The oil often is from wear around the intake valve stems, guides and the seals around the stems are hard and no longer provide a seal around the valve stems.
This is all subject to intake vacuum when the cylinder is on the intake stroke and pulls the oil in with the air and fuel.
When the engine is shut down hot, the oil is thin and runs down the stems from the head area above into the stem head area and is exposed to the intake vacuum when it is the highest except on decelleration it goes higher yet and you lose oil and don't see it while driving..
You might get some relief from an oil containing a softener but don't rely on it.
Effects of wear and age cannot be reversed with additives.
Exhaust smoke relitive color usually tells what is being drawn in.
Black usually is excess fuel but can be oil as well.
Grey usually is oil.
White is often anti freeze or transmission fluid.
The make up of the oil also has some effect on the color when passing through combustion.
Only way to clear your issue is replacement of stem seals as long as the valve stems and guides are not worn excessively.
Good luck.
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Joined: Dec 2001
Posts: 22,436
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From: Louisville,Ky.
Oil is usually more blue than grey.
I would try changing the PCV valve first. Over time, the spring in them becomes weak and allows too much oil to be sucked into the intake manifold which then gets burned in the cylinders.
If that doesn't help, you may have some valve seals going bad. Oil additives rarely work.
I would try changing the PCV valve first. Over time, the spring in them becomes weak and allows too much oil to be sucked into the intake manifold which then gets burned in the cylinders.
If that doesn't help, you may have some valve seals going bad. Oil additives rarely work.
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