Hi there,
i drive 1997 cavalier Z24 2.4 and i have a coolant leak a small one. my dad did a pressure test and found no leaks he said the pressure is holding. it is leaking on the drivers side. he changed the whole container, the coolant sensor, flange, clamps the water pump was changed 3 yrs ago. how do u know if it's the water pump? could it be the thermostat? please any suggestions would greatly help i'm going crazy not finging it it's leaking but can't find it thank you to all:confused:

It is possible to have a system that will hold pressure when tested, but that will leak a little when running. This is due to locally higher pressures in the cooling system when the water pump is spinning - which can be as high as 40 psi or a little more. Also, a hot engine may leak when a cold one will hold the pressure of the tester - which is typically about 16 to 18.
If the water pump is leaking, there would be some evidence of the 'ethylene glycol' oozing out, since the water would evaporate but not the ethylene glycol. I cant recall the layout of a 97 Cavalier, but often its not possible to see leaks from the area of the water pump just because its covered up by stuff.
In your situation I would keep track of how much coolant it is using, keep coolant always in the overflow bottle, and -when the engine is cold- remove the radiator cap and make sure there is coolant in the radiator too...then wait for the leak to get bad enough for the source of the leak to become obvious. I did this with one of our family cars for almost a year, adding water to the radiator each few days, before the headgasket finally gave out.

Hi there,
i drive 1997 cavalier Z24 2.4 and i have a coolant leak a small one. my dad did a pressure test and found no leaks he said the pressure is holding. it is leaking on the drivers side. he changed the whole container, the coolant sensor, flange, clamps the water pump was changed 3 yrs ago. how do u know if it's the water pump? could it be the thermostat? please any suggestions would greatly help i'm going crazy not finging it it's leaking but can't find it thank you to all:confused:

you state its leaking into the drivers side, i assume the leak is outside?
at any rate a changed water pump 3 years ago? was this pump autozone, or a dealer pump? aftermarket water pumps i dont trust and would only leak when engine is at normal operating temps water pumps have a very small hole at top when it starts leaking it indicates its going out and would hold pressure when car is cold and or even at idle. also has hoses ever been changed? if not start looking into changing them as its well over due on a near 12 y/o car

look for the small hole on the water pump and i bet you will see water there, if not look at all water lines, bubbles, cracking, etc. good luck.

do you smell antifreeze smell in the interior or get a haze on the windsheild? if so you may have a small leak in the heater core. just thought I'm throw it out there since it wouldn't be an obvious leak.... Good luck!