i’ve owned this car for a year and a half. a few weeks ago, my car stopped running while i was idling. it started back up without a problem. when i got home, i saw that the coolant reservoir was empty and i topped it off. last week, a faint white smoke came from the hood while i was driving. when i got home, i saw that the coolant reservoir was empty again, so i topped it off again. this morning, the faint white smoke appeared from under the hood again. the coolant reservoir was full and there were no visible signs of leaking anywhere.
It’s not white smoke, it’s steam. You have a coolant leak. If you fool around too long and overheat the engine, your repair bill will go way up.
Get the car to a good mechanic.
Have them run three tests, immediately:
“Dye test” which includes putting dye into the coolant which turns colors to identify combustion gasses in the coolant system. If it fails the test- new head gasket and machine work on the head is in order. Or indicative of a crack in the head. Expect costly repairs
“Pressure test” coolant system. Uses a small pump to pressurize the system and identify the leak-- only useful is the coolant leak is pushing coolant “outward” or outside the block rather than “inward” to the cylinder or combustion chamber.
Compression check. Using a compression gauge to determine if all cylinders are at least 130 lbs. in compression (PSI). If a cylinder is low, then it is head gasket failure.
White smoke from the hood or tailpipe is steam leakage.
Hopefully, it is none of the issues I outlined and is something simple like a leaking radiator, heater hose, coolant main hose, or heater core (although this would have other symptoms.)