Computer code says thermostat not within peramaters.
 

When I changed my antifreeze I didn't take out the thermostat.So after draining it I poured in one gallon of dex-cool antifreeze then I started with the water and only got about a half gallon in.Could a to strong of a mixture not 50-50 cause my 4.3 liter Chevy Blazer 4x4 to send out a trouble code on the code reader that the thermostat isn't within parameters.On the gauge in the car it normally gets up to one or two notches away from the 260 reading.Now since the code it gets to three or four but not all the way up to one notch away from the 260 reading.I have a new radiator,one year old but since replacing it the car run steady 190 or 2 notches away from the 260.I know its very cold out there but that didn't matter before.What do you think help me out here would the mixture cause it to run to cool.P/S the heater is working great to.

Did you put in a new 195* thermostat? If not, then do so and see if the issue goes away.

Word of advise if I may. DO NOT buy a motorrad thermy. The pile of **** cost me a low mile 4.3L by sticking shut on a VERY hot day here. My deaf wife was driving it at the time and her grandpa said the temp gauge was pegged at 260 for a good while even after it was shut off. It was so hot he couldn't even open the hood the rest of the way.

I doubt the mixture has that much to do with it.
It sounds like a bad thermostat, and I hope you mean 210*, not 260*. Mine threw the code p0128, and a new 195* thermostat fixed it.

TrevT1 is correct. A PO128 code is for insufficient temp. or coolant temperature below threshold. Always a bad thermastat. replace it with a Stant 195* premium thermostat. Motorad is junk, the only one I ever bought stuck shut in less than 30 days of purchase and cost me a head gasket job. Went back to Stant, still haven't had a failure.

Yes on the thermostat code.
 

Thanks guys for such quick answers I knew this would be the way to get the correct answer to my question.Thanks again after I replace it with a stant 195 I will let you know the results.

The thermostat out of paramaters
 

Thanks for all the reply's replaced the stat with a 195 stant problem solved.Thanks to all that answered .