ever since i bought the car i thought that it ran a little cool, around the 1/4 mark on the gauge maybe 120-130. so i finally went to change it. i put in a new 195 degree thermostat and now it only gets just a hair above the 100 degree line. i was getting heat so i guess that i am getting circulation. it a 1988 sse any help would be appreciated.

i got a bone stock 90 se and the temp stays around the 1/4 mark i think its about normal

Same here.

Sounds like you either didn't install or didn't properly install the gasket between the tstat and the housing. Some early 87-88 models never had this gasket... This is NOT the oring around the housing sealing the housing to the intake, but which seals the tstat to the housing for less coolant flow [technically, but in your case you have too much now].

The other thing is you could of had bad coolant [either wrong mixture or old mixture] previously and the new coolant dissipates heat better.

Oh ya, summer time mine runs either on or less than a hair under the 1/4 mark. Now winter time like today ~35* day, I was running about 1/3-2/3 of the 1/4 mark. With time it kept sinking..

Heh, one more ya, coolant leaks make cars run cooler. So if you perhaps didn't seal up everything perfectly, a leak, even small can make a car run noticeably cooler... hence my setup, gotta bad TB coolant pipe sealing surface something...

now i dont doubt your word but how exactly does a coolant leak make your engine run cooler?

It works by the hot coolant escaping, and pulling [cold] coolant from the overflow. Pressure is still built up, so the higher pressure higher boiling point is still there. Now obviously if the coolant level becomes low because of this leak, that won't keep it cool, but if you have a full tank and a coolant leak it sure does. Last night for example, I leak about full hot overflow bottle level in 2wks, heat off, car up to temp at first was 2/3 of the 1/4 mark. Heat on, driving 20+mi it started dropping down to the 1/3 of 1/4. My TB pipe is either rotted or the mating surface is all wrong, because I've tried fixing it 3 times, only to have the leak return. So i'm done dicking with it, and just add the coolant.

dont worry the maybe sensor reading wrong my 89 reads a notch below half way with extreme killer heat

Huh.... Assuming the radiator cap is working, I thought that coolant would only be drawn from the recovery tank when the engine/rad side of the system dropped in pressure compared to the tank when the car is off and the coolant is contracting. When the car is running, even with a leak, the pressure of the cooling system should equal or exceed that of the recovery tank preventing flow from the tank to the system.

I have seen temperature gauges act funny (reading low usually) when the sensor tip is in air rather than coolant as would happen when the system springs a leak, has an air-bubble trapped in it, or was not properly bled. Sometimes you will see the temperature gauge change rapidly up and down when the coolant alternately rises and falls enough to cover, then expose the sensor tip.

I would make sure the system is properly bled of air before making any other assumptions. Filling the engine first at the thermostat opening before installing the thermostat will help to minimize air trapped in the engine.