Jim

The temp gauge doesn't change until the moment of overflow. I watched it carefully while driving and it doesn't climb up but very little... a speck. It stays at just below half or 9 oclock. Then when sitting in idle in line for gas it started overflowing and the gauge was way up but below the Red mark. Does that tell you anything?

Bev-rolling

 

Also there are no leaks until it overflows, I've felt around all of the hoses and fittings at the radiator. There is some seepage at the fill cap, but i assumed it was due to overflow.

Can anyone tell me if I can drive the car short distances in the condition?

 

The SUDDEN increase in temperature scares me. That makes me think the temperature IS overheating but somehow it's not circulating and it's not getting measured correctly. I'd check for a sticky thermostat and check for a plugged radiator.

How long since you've replaced the thermostat? How about cleaning/flushing the cooling system? How old is the antifreeze?

 

Do the cooling fans come on? As the temp comes up, "sitting at idle" and it shoots up makes me ask.

 

You might try replacing the radiator cap. If caps' relief valve is allowing venting at too low pressure, this might allow contents to boil out enough coolant to allow overheating.

good luck

 

I'm not sure if you have tried this, to check for a bad head gasket, take the radiator cap off before you crank it and if coolant shoots up out of the radiator usually it's a sure sign of a blown head gasket. We just got a '97 Wagon that was over heating oil was not milky but the over flow bottle would boil. The head was warped .007 which is a lot. So it could be a number of things that aren't really the most apparent.