02 Malibu losing coolant

[mtnhutt]

My wife's Malibu is spraying all the coolant out of the overflow tank when she stops the car. This does not happen all the time but just like once a week. The first time I found that the cap was bad so I figured it was over pressurizing it but I replaced it and it did it again almost two weeks later. She says that the car hasn't shown that it was hot. I guess my next move will be the thermostat, does any one have another idea for me to look at? Thanks in advance.

[rhandwor]

I would check the radiator fan for normal operation is coming on and running. Then turn the air conditioning and make sure this fan is running. If these are running submit another post.
If the car is missing or blowing smoke check for a blown head gasket. Feel both hoses upper and lower for proper circulation.

[Speedy_1234]

It seems to me that you have air in the system. Also before that do you use the ac often or once in a while. First tell me if you use the ac or not from there i can tell you what to do

[mtnhutt]

I was finally able to look at the car this morning and I let it idle for a good while. Neither fan came on during this time. my wife inormed me that it only does this after she has been idle or awhile ie in traffic or prolonged red light. We live in the Houston area and yes the ac is usally allways on. Since the hurricane came through traffic has gotten worse so I think this is why this problem has devoloped. I swaped around some of the mods in the fuse box and nothing happened. I'm guessing there is some kind of a sensor that tells them to come on if so where may I find it and also is there another problem I should look for.

[Airjer_]

Make sure the cooling fan 1 fuse, cooling fan 2 fuse, and the cooling fan ground fuse are o.k. in the fuse block.

[mtnhutt]

All fuses appear to be ok.

[rhandwor]

If you have a test light check for power to the fan motor if you have power.
Hook up the test light to the positive terminal probe the ground if you have ground. Take a ball peen hammer and tap the fan motor if it starts buy a new fan motor. Try swapping the fan relays between normal and AC do this with the power off. Turn on AC and let car warm up and check if one fan runs.
Normally both don't go bad at the same time. You really need a logic probe to check if the relay gets both power and ground. If you have a wiring diagram you can do it with a test light.

[mtnhutt]

Scrach all that I checked the fans again and they both come on when the ac is on but when I kill the car and start without the ac on the fans don't come on. As soon as I start the ac the fans kick on.

[rhandwor]

My 1999 Malibu has two fans one for normal and the other one comes on with the AC I think you have had a problem with the normal operation fan and it was wired to run off the AC relay. In the summer this is fine but in the winter when you need heat your AC is shut off.
Otherwise feel the top and bottom hoses when hot they should both be hot.
If this is the case you may need a new radiator.

[mtnhutt]

Both hoses are hot but niether fan will come on until the ac is turned on, then they both kick in. I told my wife just to keep the ac on for now and adjust with the temp until I can figure it out.