# White smoke



## mleega1 (Sep 12, 2017)

I'm new to the Nissan scene, but a knowledgeable car guy. I have a 1994 Sentra 1.6 that when its cold blows white smoke that smells like antifreeze. As soon as you drive a mile or so, stops and does not do it again until its completely cold. It does not overheat has good compression and runs fine other wise. Obviously there is coolant getting into the combustion chambers through the intake, any ideas how? I'm not familiar with this engine. 

Thank in advance!


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## smj999smj (Jan 1, 2006)

Usually that means the head gasket is blown. A cylinder leakdown test might help confirm that.


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## mleega1 (Sep 12, 2017)

New head gasket and the head has been professionally rebuilt. No pressure in the cooling system at all. As soon as it warms up it goes completely away.


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## smj999smj (Jan 1, 2006)

mleega1 said:


> New head gasket and the head has been professionally rebuilt. No pressure in the cooling system at all. As soon as it warms up it goes completely away.


That information would have been helpful in the first post! If there is no pressure building up in the system, I would replace the radiator cap and, if it hasn't been done, already, replace the thermostat. As far as the "white smoke that smells like antifreeze when it's cold," this could be one of two things. "White smoke," which is actually steam, is normal to see come out of the tailpipe in cold weather. Water is a by-product of an efficiently running engine. The issue is the odor of coolant in it. Since the head gasket was just replaced, it is possible that there is still some coolant in the exhaust system that remains to be burned out....OR....coolant is actually still getting into the combustion chamber. The latter has several possibilities. The head gasket was damaged during installation, the head was rebuilt but never checked for cracks (and it is cracked), or, there is a crack in the cylinder wall of the block. If it is just residual coolant left in the exhaust, it will eventually burn away. If not, you have a mechanical issue and need to figure out what is allowing the coolant to get into the combustion chamber; again, a cylinder leakdown test would be recommended. Another option would be to send a test sample of coolant out for analysis; high levels of hydrocarbons would indicate combustion gases are getting into the coolant, hence confirming a head gasket leak/cracked or porous head/cracked block situation.


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