When i was changing the cab and rotor and plugs on my 240 i notice all the plugs had very distinctive white deposits. Reading in my haynes book this indicated its running hot. I need this car to last and dont want to blow my head gaskets or anything. the gauge never goes above the middle, although when i acquired the car i did replace the temperature compensation board.


I will admit i drive my car fairly aggressively and in the few months i have owned it i have put on round abouts 14,000 miles. Is there anything i can do to fix this problem? (driving more sanely is out of the question) I was thinking about putting in a lower temperature thermostat.

 

This chart? http://www.aa1car.com/library/reading_spark_plugs.jpg
"Too Hot" also says "absence of deposits"
Usually, light-colored crusty stuff is just from fuel additives... column 1, 3rd down; "Ash Deposits".

 

definitely looks like its in the too hot category.