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Old 06-04-2013, 01:36 PM   #13 (permalink)
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Join Date: May 2011
Location: Indiana
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White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
Team Cummins
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Originally Posted by knochenhauer View Post
Full grill block operating temp: normal range 200-214f; max 217f
Partial grill block (~70 square inch opening): normal range 172-176f; max 178f
I repeat, the grille block should NOT influence the final operating temperature.

The thermostat in your engine works basically the same way as the thermostat in your house--if you insulate, open a window, etc. it'll effect the efficiency of your HVAC system, but the final temperature should end up in the same place. If your grille block is increasing the final operating temp the equivalent scenario would be like turning on your fireplace and oven in your house during the middle of summer--if your AC system isn't big enough the thermostat will keep the AC on all the time but will never be able to get the temperature down to the setpoint.

FYI, here's a plot of coolant temp vs. time for my truck:

After warm up, the temperature should stay between the 2 bands (crack open temp & full open temp). I have a 190 deg thermostat. There's a little bit of funkyness that happens the first time the thermostat opens, because the fluid has just started to flow through the radiator the first time. Shortly after that, however, the temp should stabilize between the two temps. If it still climbs and goes above the full open temp, then all the coolant is being sent to the radiator and the engine still isn't being kept cool enough--a scary situation.

Mods like grille blocks, pre-heating, etc, may affect the inital rise, but should not affect the final operating temp. The only exception I can think of is in really cold environments with very light loading, the engine may not be able to get up to the crack open temp at all without a grille block.
Diesel Dave

My version of energy storage is called "momentum".
My version of regenerative braking is called "bump starting".

1 Year Avg (Every Mile Traveled) = 47.8 mpg

BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg):

Last edited by Diesel_Dave; 06-04-2013 at 04:09 PM..
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