coolant problem question

Hi,
i was having a problem with the engine coolant on my 1995 geo metro with the 3 cyl.
I can put coolant in the radiator and drive it for a day or so and open the hood back up and the over flow tank will be completly full and the radaitor will look empty. Does any one know what could be causing this, could it be the head gasket or something else?


Thanks in advance,

Run a compression check on your engine to verify head gasket condition. You could also fill the radiator mostly full leaving the radiator cap off then start the engine letting it warm up, watch the coolant in the radiator you should see it circualte but it should be bubble free (or nearly so) if you see a lot of bubbles you probably have a bad head gasket.

I have filled the radiator full and left the cap off and let the car run and i didnt see any bubbles, i didnt really see it circulating either, but the water slowly starts to rise and starts to spill out the top of the radiator.
I did replace the thermostat because i thought it might have been stuck since i didnt see it circulating, but even after i replaced the thermostat it still puts all of the coolant into the over flow tank.
I guess i have to try to run a compression check if i can, i dont know what else to do.
if you have any other ideas please let me know,


Thanks

With no bubbles in the coolant it makes me wonder if the pressure cap on the radiator has gone bad. Having the coolant expand as it warms up and eventually spills out of the radiator is normal. Does your car overheat? Cooling fan on the radiator kick on? I can't remember the year (I think it was 96) Metros switched over from having the electric fan controlled by a thermo switch to being controlled by the ECM. On my 94 there is a thermo switch located located on the thermostat housing If I unplug it and jumper the plug end that goes to the wiring harness it turns on the cooling fan. Possibly your switch has gone bad so you aren't getting all the cooling you need which would allow the coolant to overheat/expand and flow out into the overflow tank.

its a 95
i just replaced the radiator cap.
i will have to check to see if the fan kicks on, i dont remember.
i will look and see if there is a switch by the thermo housing.
could this also then be a symptom of a blocked or restriced coolant flow?
since i didnt see any circulation in the radiator?


Thanks for the help so far

As the coolant heats up and hits the temp of the thermostat it should open allowing coolant flow which you should be able to see in the radiator as some circulation. Have you verified the orientation of the thermostat? The "pellet" side usually goes toward the engine http://www.automedia.com/Keep/Your/Eye/on/the/Thermostat/ccr20041201th/1 If it is in backwards then it might not see enough temp to open properly. What is the condition of the radiator hoses? It's possible one of them is soft and collapses restricting coolant flow. It's also possible that the radiator is partially clogged, does the temp climb at low speeds but cool down at highway speeds or the reverse?