We all know 3rd Gens run too hot on stock 195* t-stadt. In HOT weather, or slow cruising, cooling fans are on constantly. 160 * t-stadt is fine for HOT summer weather, but questionable for cool early spring / late fall days. Temp gague barely moves, and thats not good for internal friction, clean closed loop operation, or good performance. TPIS and others recomend a 170 * t-stadt for best all around compromise / operation. TPIS, and others way overcharge for these. However, if you go to a Chevrolet dealer and ask for part # 10220957, you will get a 170 * t-stadt for a list price of just $6.92. Origional equipment quality at cheapo prices. If you just ask for a 170* thermostadt without part number, they say they do not carry them , but with that part number, guess what, they can get em! If anyone is interrested, check it out. It worked for me!

 

If you get an adjustable fan switch and a 180* or 160* thermostat you can control your fans better and you can get cooling in the summer and still have heat in the winter. I know, cuz I do it The computer will go into closed loop at as little at 130* as long as the O2 sensor has reached it's proper temperature. As a matter of fact, I believe those that custom program their own chips can get closed loop even quicker than that. So you see, closed loop is not a problem when it comes to t-stat. IMHO, I think the t-stat you use is based on your own opinions and there is no right or wrong. Personally, I feel paying the extra money for the 170* is pointless but if it suites you well then go for it. BTW, TPIS is a joke!

 

I have to agree with 86, if the eprom is properly tuned it really doesn't matter (from a performance persepective) from a 160, 180 or 195 - they will all perform the same.

I personally prefer a 180* over a 160* as I can get more consistent performance with a 180*.