94 Nissan sentra is leaking radiator coolant however do not know where?

Question

Every 3-4 weeks i have to add coolant to radiator i have changed the radiator, radiator cap, changed waterpump about a year ago. I have checked all the obvious areas for a leak and cannot figure out where the coolant is going. The only thing that I haven't changed is the overflow bottle and lower hose. Everything else has been changed withing the last year and a half. Does anyone have any suggestions for me I would really appreciate it Thank you

thanks for your responses. To answer your suggestions no milky substance in oil cap, no white smoke at anytime, already replaced radiator cap, have done pressure test that is how i found crack in radiator replaced radiator, the only thing i haven't tested or replaced would be the overflow bottle somehow could it be leaking from there? This is why it is so frustrating I have pretty much done all the right test without spending a fortune taking it somewhere. I would appreciate some more feedback thank you

I have checked the heater core and for fluids of anykind on floor of car non detected. Could fluid evaporate if overflow bottle is not air tight? This is the only thing i really haven't checked. Your input is greatly appreciated.

Answer 1

I use a radiator pump. It puts about 15 pounds of pressure on the water, sometimes the leak is immediate, sometimes you have to leave it overnight. Sometimes you can't find the leak and some months later you need a head gasket and you figure that must have been it. Does your oil filler cap have chocolate milkshake inside.
Do you spark plugs appear a little like rust on the porcelane inside.
Keep us posted.

Answer 2

You didn't mention how much coolant you need to add each time but it must be a significant amount. You should get your cooling system pressure tested. Connect a pressure tester and pump it up to the pressure rated for the car (or the rating showing on the cap). Leave it pressurized for at least 15 minutes. If the pressure drops you have a leak somewhere and need to track it down. It may be internal if there is no leak outside. If the pressure holds then it may be a problem that only happens when the engine is hot. To check this, connect the pressure tester but do not pressurize the system. Start the engine and watch the pressure buildup as the engine gets hot. If it shoots up high quickly, you may have a head gasket leak. If it gradually gets up to 15 psi and no leaks are apparent then the system is probably fine. If that is the case, connect the tester adapter to test the cap, which is probably the culprit if everything is ok. Also check the rating on the cap and make sure it matches the required pressure rating for the vehicle.
Note: If you have any oil in the coolant, coolant in the oil, or white smoke in the exhaust you may have a head gasket leak. If the vehicle is automatic, check for coolant in the tranmission or auto trans fluid in the cooling system. That would indicate a leaking trans oil cooler in the radiator.

Answer 3

I would find a clean spot to park over after you have sufficiently run the car long enough to pressurize the cooling system and let it sit and run and observe under the car for a few minutes. You should be able to find the area where it is leaking. Make sure that the overflow is sealed tight.

Answer 4

Look at your tail pipe, car running. White smoke? That's steam. You have a water leak letting coolant into the engine, intake or head gasket bad. No? Get a large piece of cardboard, park on it overnight. Drive off in the morning and see where the drip is. Look there for the leak.

Answer 5

snap on offer a detection kit which draws coolant vapor through a liquid. a colour change indicates exhaust gasses are present in it. this indicates a defective head gasket. it's also possiable that the cylinder head is cracked. which requires a different test

Answer 6

Heatercore is leaking. Check the floorboard on the passanger side and check for the smeel of antifreeze in the car. Also see if you have a film of antifreeze on the windsheild when in defrost mode.

Answer 7

OK check your radiator to make sure core isn't leaking, check your heater hoses both to the firewall & to waterpump, check heater core (is your passenger floor wet?), if wet that's heater core.

Answer 8

start the car and look at the hoses that comes from the rad and you will see the coolant when the pressure gets up on the car

Answer 9

if you say you havent repalced the lower radiator hose you should do so. and if you have the 2.0L you should ask the same question with as much detail as you did here but on SR20forum.com in the technical corner section they may know also.

Answer 10

first thing you should do is to flush the radiator in the opposite flow of the water in the engine with a top water,,then if the problem still the same,Start it in a cold engine open the radiator cap and give the engine throttle a quick jerk open ,,if the water flows out,,, then you got a blown cyl head gasket and need to be change,, good luck