Running Temp?

White smoke - you sure it's not just the condensation that occurs as it gets colder outside? Engine's burn gasoline in oxygen - the biggest byproducts of combustion are H2O (water) and CO2. When you start up a cold engine, that water in the exhaust stream condenses out in the cold exhaust pipes/mufflers - so you see water spitting out the back and a stream of vapor/fog out both pipes until the system warms up enough keep the water evaporated. If you have only short drives in the winter, you can have 'white smoke' all the time -- very hard on the exhaust system in terms of rusting from the inside out.

If you're loosing coolant out the exhaust pipes (as in failed head gasket) 2 things will happen - 1) you can smell the antifreeze in the exhaust very clearly. If you're not smelling antifreeze in the exhaust stream, then you can't be loosing too much there; 2) your coolant level will be lower. Are you having to constantly add coolant?

Assuming that's not the problem, you probably have a t'stat that has failed and it's stuck open. Upon failure sometimes they stick open and sometimes they stick closed. When they stick closed, you overheat quickly. When they stick open, the car won't warm up.

Hope that helps.

The new ones have been known to be bad right out of the box - and can go bad in short periods of time. You didn't mention if there were any other symptoms, or if you're losing coolant.

If the only symptom is the temp gauge is reading lower - it pretty much has to be that either the gauge/sender is malfunctioning, or the t'stat isn't closing down all the way allowing too much coolant to go to the radiator too soon.

U should not over heat with a 190 thermo, not possible unless something is not up to spec.

I a 190 thermo and run cool even in the PEAK summer in WA !!

When was the last time U cleaned the radiater??
How many mods do U have??

Your TB is sticking, clean it and see if it is adjusted to far closed.

U ran hot with the 190 thermo because of the pulleys U have on the car.

Install a high flow 180 (mr.gasket in the summer and a 190 in the winter, that what I do.

Good Luck and hope to see U at the next meet !