Q: White smoke at starup on a '98 Maxima

That is a classic sign of the blowing head gasket. What you’d want to do first is watch my video "how to tell if your head gasket is blowing." If it is, you’ll need to figure out whether you’d like to spend a bunch of money on a new head gasket, or to get rid of the vehicle right away, as this is a very expensive to do a head gasket.

When it is blown, you don’t know if the head has a problem or not until you take the head off the engine, which is a very big job. Someone might say, "I’ll put the head gasket on that for 1800 dollars," but then they take it apart and say "Oh that’s going to cost you 4,800 dollars." So you won’t even know until you take it apart. The car is so old that I don’t know if you’ll even want to spend that kind of money. Do the test first and pray it is something else.

Sometimes it might be a leak in the fuel injector. If this were the case, fuel would flood the engine and make it smoke and then cause a gas-like smell. So do the test first, or have a mechanic inspect the smoke problem for you.