View Single Post
Old 07-12-2008, 05:33 PM   #5 (permalink)
EcoModding Apprentice
Join Date: May 2008
Location: South Dakota
Posts: 117

GMC Sonoma - '94 GMC Sonoma
90 day: 36.97 mpg (US)
Thanks: 0
Thanked 4 Times in 4 Posts
Originally Posted by scissorhands View Post
In theory wouldnt engine off cruising have the potential to crack engine blocks or heads? S...
My thinking is, if that condition was enough to crack the block or heads then they would already be cracked from normal driving.

The first time the thermostat opens, after you begin your morning commute, the radiator has coolant that is the temperature of the out of doors, perhaps as low as -20F on a December morning. But at some point the T-stat opens (engine finally reaches +195F) and the cold coolant rushes in. But alas the engine survives it, day after day.

For that matter, I expect the radiator coolant probably cools back down to near -20F every time between when the T-stat closes and then again opens, at least on a -20F winter day.
  Reply With Quote