1997 geo metro 4Cly Auto Over heated and...

Ok so about a week ago we drove the car on the highway about 35 miles doing 60-65MPH, near the end of the drive I glanced at the temp gauge it looked normal, after we stopped and got out we could smell it over heating turned the key back on and the gauge was real high, we opened the hood and there was coolant on the underside of the hood a little on the top of the engine, I checked all the hoses and the water pump and radiator cap everything look fine, I coudn't tell where it came from. So after letting it cool off I added some water about 1 QT was all it needed. We drove back home (the same 35 miles) and it was fine no over heating or anything since then I have checked the coolant twice and both time it was a little low only about half a QT, there was no sign of coolant anywhere under the hood or on the ground where we park it.

So my question is what would have caused it to overheat that one time and not since? and where is that coolant going?

~Zechariah

P.S. I once had a '89 toyota camry that had a cracked block there was oil in the coolant and coolant in the oil, I have checked the oil and there is no sign of coolant and no oil in the coolant.

Depends on the conditions. Maybe the T-stat got stuck temporarily and then some coolant escaped the overflow? If it is consistantly losing coolant, it may be getting burned in the combustion chamber. Remove the spark plugs and see if they are white and powdery looking.

Alright I'll check the plugs.

~Zechariah

So the spark plugs were new about one month ago, I just checked them and they all have a yellowish bunt looking spot and a slight hint on grayish powdery stuff on them, also there is oil residue on the threads.

Is this a bad sign? what does this show?

Thanks for the help,
~Zechariah

If the radiator cap is bad or doesn't hold pressure it will cause coolant to overflow out the overflow container and overheat. Sometime the cap is overlooked. Fill up the system again, purge the air from the cooling system and let the car idle until until it's fully warmed up.

Check for coolant leaking. If it leaks out the overfull containger, change the radiator cap.

Does the car run good?

If the car runs bad, you will want to run a compression test to check for blown head gasket.

Also pull the dip stick to check for coolant in the oil.

If it were my car and it runs good now, I would replace the stat and cap if they haven't been changed in the last 3 years. If it runs bad, I would do a compression test.

is the car smoking whiteish out of the exaust and if so does it have a burnt sweet smell

Make sure you turn on the heater when purging out the air. once the air is out you should not loose any coolant if there is no indication of a leak any more then could have a bpwn head gasket. best to have some one follow you whle you drive it warm and see if there is any smole coming from the exhaust.

Okay so I started the car today and turned the heater on all the way about 10 minutes later I went out and it was running a little bit hot and there was water dripping out of the tail pipe and white smoke. What does this mean? bad t-stat? water getting in the cylinders? how?

Thanks to anyone who can help me,
~Zechariah

Cracked head or bad head gasket.

No need to turn the heater on in our cars. Some cars have a valve controlling flow through the heater core, ours do not. 200 degree water is flowing though the heater even when it's turned completely off. One of my favorite design features when it's 100 degrees outside.

Okay thanks for the reply, I'm leaning towards head gasket because, theres no water in the oil, am I right to think this or not? oh and the plugs have a slight whitish powder on them. If it was a cracked block wouldn't there be water in the oil?

Thanks again,
~Zechariah

Either way, you will have to pull the head and inspect. These are easy to rebuild and can be done at home with hand tools.

Alright thanks for your help, I'll have to wait till the weather clears up before I can work on that.

Thanks Again,
~Zechariah