Q: Misfiring Engine

asked by on October 13, 2016

I recently bought a 2002 Altima from a used car dealer. Drove it for about a week, and the check engine light came on. Had a mechanic look at it. His computer said that engine misfires were detected. Had a co-worker look at it, and told me that I had a blown head gasket...but the mechanic didn't tell me that. Shortly after, I begun noticing slight problems starting the car. Then the car wouldn't start at all! After taking out the spark plugs and cleaning them, the car started. After driving it, I noticed white smoke coming from the bottom right side of the car. I'm told that I may as well get a new engine over getting just the gasket replaced, because replacing the gasket will apparently cost more. What should I do?

My car has 147000 miles.
My car has an automatic transmission.

Hi and thanks for your question. When you see white smoke coming from the engine or at the tail pipe, this is water and ethylene glycol mixture burning off. The smoke should smell sweet. If the smoke smells sweet, then you probably have a blown head gasket. But to verify this, you would need to get a block tester. Put the blue fluid into the block tester and place it over the radiator cap neck with the cap off and the engine running. As steam comes out of the radiator, squeeze the plunger and suck in only the steam. If the blue fluid turns orange or yellow in color, then you have exhaust gasses entering the cooling system. This would be a sign of a burned head gasket. If the fluid does not change color, then there is no burned head gasket.

You could have a warped head causing the coolant to leak out of the head and onto the hot exhaust. Or you could have a coolant leak coming out of the engine’s casting plugs and leaking onto the hot exhaust to get the white smoke under the engine. Your vehicle could have an exhaust leak to make the smoke leak out to if there is a blown head gasket. In order to get this fixed, I would recommend having a certified professional, like one from YourMechanic, check out the white smoke issue to avoid any unnecessary repairs.

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