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2006 RAM 1500 - Question on thermostat

Had to replace the engine thermostat in my 5.7 hemi. Called the local dealership and they said it took a 190 degree. upon removing the old one it showed 200 degrees. The gauge now stays at just left of center, but well within the operating range. Will this 10 degree difference reduce the life of my engine? How about it passing Ca smog tests? Thanks, Walter



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The cooling system operating temperature for the 5.7 liter engine is 203 degrees F, this temperature was selected for reduced emissions output. I wouldn’t expect the person who answers the phone at a car dealer to know this. Even the parts department counter clerk doesn’t need to know this, there is only one replacement thermostat in the parts catalog for this truck/engine.

Using a lower temperature specified can set a fault in the PCM and illuminate the check engine light.