Jim,

This example is my truck since I have an EGT gauge but my readings vary from around 200F to 1200+ depending on the load. The temps will ramp up sharply under any significant load but generally hover around 500-600 while cruising down the highway. The exhaust manifold and turbo will glow red hot under load for an extended amount of time.

A diesel is very effecient thermally and it just doesn't generate much heat at idle.

If you're going to mess with modifying the engine for WVO or otherwise, you would be smart to go ahead and invest in an EGT gauge for your car. Teamed with a boost gauge, even in an unmodified car, it's interesting to note the readings and it can also help you drive for maximum economy.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250