What can cause white smoke from the exhaust?
- It often means that you are burning antifreeze. You asked if it
needs antifreeze, have you noticed any leaking out of the reservoir
tank while you are running it? Sometimes when the head gasket goes
it will produce a passage for the antifreeze to pass from the
capillaries into the combustion chamber. It is easy to check if you
have an air compressor. Remove one of the rear sparkplugs and the
radiator cap. Fill the radiator and then push some air into the
sparkplug hole (get a good seal in case a valve is open). Repeat
with all the cylinders and watch for air bubbles coming up into the
radiator. If bubbles come up or fluid is pumped out, the head
gasket is blown and must be replaced. It is more likely to happen
at the back of the engine because it is farthest away from the fan
and therefore gets less cooling. Also check your oil for
discoloration. If it is a brownish color it could mean your oil and
antifreeze are mixing and has the potential to damage your
- If the exhaust billows white smoke for a few seconds when first
starting the engine after it has been sitting for a while, such as
overnight, and then runs normally, it could mean that the rubber
valve stem seals have perished - especially if the vehicle is a few
years old and has done over 60/70,000 miles. Another clue is: does
the exhaust smoke smell like fresh, rather than burnt oil.
- After going nuts trying to figure out sporadic tailpipe smoke
on my Nissan Maxima, with no other negative engine symptoms, I
eventually stumbled upon a malfunctioning PCV valve. The ball-check
wasn't fully seating, allowing small amounts of oil to sneak past
and into the combustion chamber. A cheap and easy fix.
- White smoke or semi white can be produced in several ways. One
way is oil this is normally a whitish blue to blue smoke and has
the apparent smell of oil being burned. Next could be antifreeze
when it is being burned it has a sweet type of smell and tends to
dissipate in the air rather quickly. Next is automatic transmission
fluid which is normally found on automatic transmissions and its
normally drawn into an engine thru a vacuum line via a defective
transmission modulator valve or some other defective part.
Transmission fluid is very apparent and billows out so bad that you
can't see anything behind you. Last but not least another type of
smoke that is not white but black is the presents of to much
gas/fuel being burned in the engine. PS the one good thing about
transmission fluid being burned is it is an excellent way to clean
the carbon out of an engine.
- Black smoke is burning oil. Blue smoke is usually transmission
fluid due to a leaking modulator valve in the older auto
transmission. White smoke is due to water getting in to a cylinder
from a bad gasket, cracked block or a cracked head. cracked heads.
Mine started misfiring, with new plugs. Smoke came out the exhaust.
Result, low compression in the cracked head. When car was cold it
ran fine. After it got hot, the crack in the head would open up,
hence, sputtering. I've had to replace 3 heads. Everytime I've had
to have this done, I had to buy a whole new head gasket.
- After extensive research I came to the conclusion that TOO much
oil is also a main culprit for white smoke out of the exaust.
- I changed the PVC valve, the breather and the air filter and
it's good as new.
- There are a lot of incorrect answers here... but for the most
part, you can hold true to these: Blue smoke is primarily from
internal engine wear. If it's constant when the engine is on, then
the rings etc are worn and need to be replaced. If it only is blue
when the engine is cold or first started, the rings are worn but
not gone completely. You get the oil seeping during the night and
it burns off when the car is started in the morning. Black smoke is
a fuel/air mixture suggestion problems with injection or
carburation. Cause of black smoke is due to running rich in the
fuel air mix. White smoke can and DOES come from coolant burn off
in the oil due to a leaking or blown head gasket, cracked head etc.
If you aren't sure or you don't know what you're talking about,
don't advise. Wrong advice can be more damaging than the actual
- White smoke is caused by engine coolant/Antifreeze being
processed in the combustion chamber(s) of the engine.....ie
burning, melting, frying, whatever....Period....I'll explain
further.... This is automotive chemistry 101....Oil of any
automotive type burns blue.....too much fuel issues burn black not
enough fuel issues burn grey on a cold day you may see what appears
to be white smoke from the exhaust that will disappear after the
vehicles engine has warmed up to it's normal operating temp.. This
is a normal reaction called condensation... condensation is the
result of a small amount of water/dew being drawn into the exhaust
usually collecting in the muffler and/or the catalytic converter
and is caused by our friend mother nature..... like when you see
your breath on a cold day...
- I am a highly experienced ASE certified automotive repair tech.
I have over 16 years of diagnostics and repairs to my credit..I
have made a very good living in the automotive business by being
precise with my diagnostic procedures....I have worked for 3 of the
largest rental vehicle companies in the country.... I have
diagnosed and repaired an estimated 200 vehicles to date with the
white smoke issue... every vehicle that i mentioned had engine
coolant/antifreeze entering one of the combustion chambers in the
engine... Most of these vehicles had a damaged head gasket(s).. the
most common causes of this issue that i have detected over the
years are due to improper maintenance of the engine cooling system,
severe overheating of the engine, improper tightening of the
cylinder head(s) during an engine overhaul,or some other type of
repairs that required the head to be removed and also defects in
manufacturing of the gasket or the engine... i have seen evidence
of careless repair techs that have scratched or cut the surface of
a replacement head gasket with either a tool or the cylinder head
during the install process.. sometimes it will never cause an issue
but it can... i am very careful when dealing with any gaskets but
especially head gaskets due to the amount of work involved in
replacing one on some vehicles.. bottom line, I'm not fond of doing
the job twice so I'm careful the first time... I have seen improper
cylinder head or engine block servicing techniques cause failure of
the gasket(s) these types of failures are generally caused by
improper cleaning of the gasket surface of the engine block and/or
the gasket surface of the head.. i have also repaired or replaced
cracked heads and in extreme scenarios i have replaced cracked
blocks and severely overheated engines with a new or
re-manufactured engine due to such severe damage to the internal
engine components or block .. There are a mix of correct and
incorrect answers to your concerns by the participants that have
replied.. I can assure you that almost every well trained tech will
answer your questions as i have.. I'm not saying I'm an automotive
god, I am just proud of the priceless knowledge that i have
acquired...FYI, I'm a graduate of Denver Automotive and Diesel
College in Denver Colorado.... DADC is one of only two Automotive
Technology colleges in the country with the intense hands-on and
classroom teaching practices to properly train a truly, highly
skilled automotive/diesel tech who can easily handle any diagnosis
and proper repairs of yesteryears and today's automobile
- White smoke CAN be caused from oil....I have fast-road engined
1987 Golf Mk II. If I boot it hard on tight corners, roundabouts,
etc, it can cause oil surge in the engine and some oil can 'slop'
into a cylinder. The James Bond style smokescreen it produces can
be very exciting for drivers behind me!
- Lots of good answers; I just want to see if I can clarify from
my experience. SMELL!! Good mechanics without great diagnostic
tools learn to SMELL. "Burning" (yes, technically it's boiling, not
burning) Antifreeze smells 100% different than burning OIL. Let
your nose be your guide. The Antifreeze will have a sweet sort of
smell--hey--kinda like antifreeze smells, and it will make your
eyes tear up and your throat lungs will tell you to get out of that
toxic fog right away. Also--the timing. Yes, when forming a good
question, you need to give GOOD DETAILS. Does it ALWAYS burn white?
Just at startup? Only when hot? Etc. DESCRIBE, DESCRIBE,
DESCRIBE!!! A head gasket problem is ALWAYS there and it only gets
worse under pressure/acceleration/load. It will go from a little
cloud to it's own weather system when you stomp on the gas.
- OVERFILLING THE OIL will produce this white burned smoke too.
Yes, it will SMELL different. IT will also usually go away after
some driving. CHECK THE DIPSTICK, it's obvious, but do it--do it
right. Flat surface; cold engine. Pull--Wipe it off--put it in--now
you are getting the real level. Oil burning will be at startup from
worn valve rings/seals and during driving from overfilling at first
a lot, then only at heavy acceleration/g forces when demand is
high. Again--smell, check all your fluid levels (OIL, WATER, TRANS)
of course, whatever is low is what you are BURINING (or for the one
gent that gets particular, boiling). ALWAYS Start w the simplest
thing or the cheapest. Did you just change the oil and it
started--overfilling, etc. Yes, it won't hurt to check the PCV
valve and tubing. Really, check all you can check.
- My problem with white smoke was whenever I would be going down
the road at high RPM and let off the trottle. Then it was like a
smoke bomb went off. Bottom Line.......... My Vacuum Modulator went
bad on my transmission whenever high vacuum was created it was
sucking transmission fluid into my intake manifold and thus into my
combustion chamber creating white smoke. Replaced the modulator for
$12 and everything is right with the world
- i had the exact problem with my Mazda down to a T. All we had
to do was buy a bottle of engine sealant... it takes a full day to
run thru so follow directions exactly. Now the car has no
problems... full power is bacl no more "smoke bombs" and no more
dying at strange times.
- Steam or smoke is the question here. If its steam some
considerations are what year is the vehicle newer catalytic
converted cars emit steam and water from the exhaust and you should
be cautious about the blown head gasket or cracked head syndrome,
if you suspect a blown head gasket or cracked head go to a
reputable shop that can confirm exhaust gasses in the coolant. You
will notice a low coolant level and a peanut butter looking
substance on the oil cap (possible traces of water and coolant in
the oil but generally engine pressures will prevent this. Be
prepared for the worst and hope for the best. If it is smoke a
thick white smoke it could be transmission fluid being pulled up
through a vacuum line to the intake manifold and being burned, this
was quite common on older Ford and Chrysler vehicles that had a
vacuum shift solenoid and an automatic transmission.
- Has your car severely overheated recently? Does the smoke smell
like antifreeze? If it does, you probably have a blown head gasket.
The "smoke" in this case is actually steam from water leaking into
the cylinders. Also check for yellow or white goo on the oil cap
and dipstick, indicating water leaks to the oil.
- Your symptoms are indicating a possible head gasket problem.
You have water going into the combustion chamber and coming out the
back tailpipe as steam. You may also have exhaust gas in the water
which can also be checked by a mechanic. Be prepared for the
expense of a head gasket or possible engine replacement.
- If it is not happening all of the time at operating temperature
(head gasket as mentioned before) and it occurs just at startup. It
may be that due to heavy moisture in the air, dew, a heavy rain,
will build up moisture in your exhaust system. At initial startup
until the vehicle is warmed up and run for a bit, you may see thick
- I had an old engine that sucked oil through an intake valve
when the engine went fast enough. If you burn enough oil it looks
white. Especially in Michigan on a cold morning.
- I had this problem with my '96 Ram after an overheat. A cracked
head gasket was allowing antifreeze to get into the combustion
chamber and creating all kinds of white 'sweet smelling'
- White "smoke" in cold weather is just steam. When gasoline
ignites it produces quite a bit of heat and expands to several
times the original size, creating high pressure on the piston. That
pressure causes the piston to move down, turning the crankshaft
which makes the car go. When the fuel ignites it causes a sudden
and violent chemical reaction between the the oxygen in the air and
gasoline (which is a long chemical molecular chain of carbon and
hydrogen) resulting in carbon dioxide and water vapor. As the water
vapor cools in the exhaust pipe it starts to form small droplets
that are visible in the form of steam vapor. That's the white
smoke. Once the exhaust pipe warms up sufficiently, the exhaust
leaving the pipe is still hot enough that the water vapor hasn't
formed the droplets and dissipates quickly enough that you don't
see the vapor. On the other hand, if it's light blue or blue-grey
smoke and it doesn't stop when the exhaust pipe warms up, that's
oil vapor and a sign of bad rings and/or valve stem seals.
- white smoke is usually caused by condensation in the combustion
chambers. This will usually dissipate once the car has warmed up.
If it persists there could be difficulties with: Problem: Solution:
Moisture in fuel Apply one cap full of Methylated spirits to fuel
tank (This is quiter safe by the way, it dissipates water) Head
gasket leak Replace head gasket, approx $500 AUS (other symptoms
such high temperature will also be prevailent.) Failing these two
suggestions, there is a slight chance of moisture in the oil sump.
this is rare if the head gasket is ok. Simply check your oil level,
if the oil looks milky, there's the problem. Also if it is milky,
replace the head gasket.