rburt07 — I think your dealer is misinformed, to say the least! I'm sure that the 2008's ICE is identical to that of the 2007, and the block heaters would thus also be the same.
It's important to understand how a block heater works. It generates heat at a rate proportional to its rating in watts. These are 400-watt heaters. This heat raises the temperature of the engine block until the rate at which the block loses heat to its surroundings equals the rate at which the heater is generating heat. Then the engine block stops rising in temperature. It therefore does
not reach any
specific temperature, but rather the block temperature rises until it is
a specific amount above the ambient temperature (
i.e., the temperature of the surroundings). I find that my block heater will raise my engine block's temperature ~30 degrees C (~54 degrees F) above ambient. It takes about 2.5-3 hours to do so. This means that, given enough time, the block will ultimately reach, for example, ~84 degrees F if the ambient temperature is 30 degrees F. It will not rise any higher, no matter how long you wait! This is consistent with your readings.
By the way, the TCH's temperature gauge reads as follows, according to my ScanGaugeII:
- bottom of blue area = 35 degrees C (~95 degrees F)
- top of blue area = 45 degrees C (~113 degrees F)
- heater starts operating = 47 degrees C (~117 degrees F)
- ICE cycles "on" to provide cabin heat = 53 degrees C (~127 degrees F)
- ICE cycles "off" again = 57 degrees C (~135 degrees F)
- 1 tick mark below center of scale = normal operation indication = 60 to > 93 degrees C (~140 to > 199 degrees F)
So, over the temperature range of 35-60 degrees C, each tick mark on the temperature gauge represents precisely a 5-degree C temperature change.
The following is speculative, since I have yet to see my ICE temperature rise above 93 degrees C:
- bottom of red area = 120 degrees C (~248 degrees F)
This means that the gauge sits at 1 tick mark below the half-way point from 60 degrees C until some (as yet unknown) higher temperature above 95 degrees C, and then starts to rise again. This has probably been done to prevent users from becoming worried, as the temperature is continually rising and falling as the ICE cycles "on" and "off."
Stan