Drove thru ditch with water very deep on exit saw white smoke and running rough now on new start it productes white smoke untill engine gets up to speed and then runs good but an engine light comes on. also the gas milage has gone from 16 to 6

The alternator is used to charge the battery. There is no reason to believe the replacement has caused the fuel utilization problem, or smoke from the tail pipe, or rough running engine. A good mechanic should be able to examine your engine and find the problem. White smoke could be valves or piston rings worn out. There are many things that cause rough running engine. Fuel mixture controls, fuel leak, faulty timing, there is a long list. Good luck.

Blue/grey smoke is typically engine oil burning.

Grey/black smoke is typically excess fuel (or insufficient air).

White smoke is invariably water that has turned to steam. (water is a natural product of combustion as well as the stuff the head gasket keeps out of the cylinder).
Sometimes an engine can emit a fine mist of unburned fuel that seems like white smoke.

Clearly your engine is burning some engine oil. Perhaps the valve stem oil seals are failing. When an engine noticably burns oil it must be realised this isn't good for the oxygen sensor and catalytic converter and it is inevitable the life of these things will be shortened.

It is doubtful the replacements you have so far carried out will have changed anything and it is likely to be coincidence the colour of the smoke has changed.

What is needed is a diagnostic check to inspect the live data from the sensors when it will probably be found one or both oxygen sensors will need replacing and perhaps other things have grown tired too - at an extended mileage an injector could start dribbling or the spray patterns be so poor the engine won't be able to burn it all and then it will be expelled into the exhaust.

Hi Mark,
Probably water is in the fuel, and the distributor could have moisture in it. The best way to clean the distributor, is to use denatured alcohol, also called methylated spirits. Dry off the distributor cap and the rotor button, then wash with the alcohol. This will mix with any moisture, and when you empty the distributor cap, all the moisture will also be removed. Allow it to dry off - evaporate, and its moisture free and ready to go.
You can also put 1/2 pint, or 500 ml of the same alcohol in your fuel tank - it will mix with any water, and pass through your fuel system without any harm.
Hopefully you will be able to fire up your van now, and have trouble free running, that is if you keep it out of ditches!

Changing the plugs probably had nothing to do with it.
White smoke is usually a sign the engine is burning coolant or trans fluid. You might want to check those fluid levels.
If the coolant is low, you may have a leaking head gasket or intake gasket.

You have a failed head gasket

Major repair

Hope you didn't think the stop leak was
a genie in a bottle,never need any product
in any vehicle,just the proper repair

White smoke was coolant ,should have known that

It's possible that the white smoke you are seeing is from coolant entering the exhaust, however, I would think that the engine would also be running rough or be difficult to start should this be the case. I would start by checking the coolant level. If the level is very low then it's possible that you have a head gasket leaking which is allowing coolant to enter a cylinder and then be forced into the exhaust where it will turn into a thick white steamy/smoke that takes a while to dissipate after it exits the tailpipe. Whatever the source or cause of the smoke is, it's possible that it could cause some serious engine damage so you should have it checked out as soon as possible.

White smoke and running roughly would normally point to a head gasket problem.

Keep an eye on your engine coolant I'd imagine it will start to disappear.

You need to replace the intake plenum. Are you losing coolant too?.

um this proboly u went trough a deep water the water hit the exhaust and just burned water ur horn got water in it but nothing to worry about how to fix it normal day use ill go away i promise

white smoke is antifreeze try checking the compression