[FirstOwner69]

I am not a mechanic, nor I am not an expert. What I'm going to say may start a huge debate.

I do not consider 210 degrees "over heating". I call that "running hot". A system with a 15# cap and 50% ethylene glycol will not boil until it reaches 265*. Sometime during the 60s, GM vehicles changed to 195* thermostats primarily for emissions purposes. Simply stated, engines are supposed to run cleaner at higher temperatures (I imagine to a certain point). I've had 4 later model Chevy pickups (a 1986 dually with a 454 and 3 Duramax duallies). I have towed heavy loads up steep grades with all of them. The auxiliary fans never kick on until the gauge is at 210*.

Are you still running an A6 compressor? If so they place a higher load on the engine than the Pro10 replacements or the more modern compressors. A temperature rise is normal., certainly at idle. I wouldn't be too concerned about higher temps, say 210* or below, unless they are routine when driving at highway speeds.

Let the debate begin!