Nissan LEC 1994 sentra water leak problem

Most plugs are gap correcly out of the box.
Thread spark plug gaping size for all nissans

can you please tell me the location of the fill plug oil for transmission? engine is GA13S.. thanks

I would check that spark plug, and have that coil checked or replaced. Also check for any vacuum hose leaks in the area of the cylinder.

if you're referring to the thermostatic valve in the coolant line, then yes, yes it does have that. it's located at the end of the upper radiator hose (return line) close to the engine. it's inside of what may look sorta like an elbow pipe.

How many miles on it?
do a compression test to see how worn the piston rings are

There is no carburetor on your car, it is fuel injected. Your coil is what fires the ignition. You can buy a Haynes manual, which has a troubleshooting section in it, but it sounds to me like you aren't really too sure around cars, so i'm going to suggest you find a reputable mechanic to take the car to. It may be a simple problem, but if you aren't comfortable working on cars, the mechanic is the best route. i'm sorry not to be of more help, but problems like this one can be caused by a variety of things only diagnosable while with the car to test as you go.

Regards,
matt

check air flue meter stick a matchstick into the hose if this works change air flue meter allso check sparkplugs

Could be an expansion valve or as well as the car might need a top-up of gas?

Check the freeze plugs on the engine block.
These plugs/caps can leak when it is not sit perfectly.
Is the leak from tail pipe or from the engine area?
Start monitor for coolant and oil lose and report to the engine supplier.
Can you have a friend to do a drive along to see where the white smoke is coming from?

DO NOT rule out an incorrectly install head gasket set.

Make sure the PVC system is not plugged or disconnected, this causes pressure in the crankcase and hence the oil in the air cleaner, seen it many times