when to plug in ?
Post Fiend
Joined: Feb 2002
Posts: 10,600
Likes: 3
From: Carhenge
A 7.3 engine in good condition with a properly operating glow plug system and good batteries will readily start at -20*F without being plugged in. I don't even consider plugging mine in unless the forecast is for lower than -10*F.
Posting Guru
Joined: Dec 2006
Posts: 2,498
Likes: 3
From: Windsor, Colorado
Originally Posted by clux
A 7.3 engine in good condition with a properly operating glow plug system and good batteries will readily start at -20*F without being plugged in. I don't even consider plugging mine in unless the forecast is for lower than -10*F.
Lead Driver
Joined: Mar 2000
Posts: 9,359
Likes: 1
From: Hampstead, NC
I have a heavy duty outdoor timer set to come on at 12AM and off just after I leave at 4:30AM. I like the idea of having a warm truck first thing, not 6-10 miles down the road. Plus, I don't like going out in the cold to start it. I'm testing it out for the first time tonight.
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Posting Guru
Joined: Mar 2007
Posts: 1,905
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From: East Peoria, IL
Originally Posted by medhvac
nice pic kris thanks for showing that!
what he said..thanks for helping us all visualize the portion of the block heater most people, like myself, havent seen. it helps us understand exactly how it functions
Post Fiend
Joined: Feb 2006
Posts: 11,892
Likes: 2
From: Middle Tennessee
I can say that I have plugged mine in the first thing before going hunting. Even 30 minutes makes a big diff. If not, your heater is on it's way south. I do not care how cold it is. If after 30 minutes there is no diff, it ain't working. One hour seems to be the magic number for mine. Even in the 20s, it doesn't get any warmer until I start it so I say one hour is good. Pretty much a water heater element. They fail after a while.
Edit: Great pic Kris. A water heater element. After one hour, how much warmer can we expect the block to get in the teens? No insulation there so I think anything over 1 hour is a waste as it is frittering away. Of couse in -30 temps, probably a good idea to run all night. That is brutal.
Edit: Great pic Kris. A water heater element. After one hour, how much warmer can we expect the block to get in the teens? No insulation there so I think anything over 1 hour is a waste as it is frittering away. Of couse in -30 temps, probably a good idea to run all night. That is brutal.
Last edited by Tenn01PSD350; Nov 30, 2007 at 12:07 AM.
Senior User
Joined: Oct 2004
Posts: 376
Likes: 0
From: South Dakota
I usually plug it in when temps start dipping below 30'F for about 3 hrs. Less than 0'F then I usually leave it on all night. I have forgotten to plug it in and temps got down to -15'F ans it still started. Didn't like it but it started.
New User
Joined: Jul 2004
Posts: 8
Likes: 0
From: Iuka, MS
I have been driving a diesel for 6 years now and I plug mine in anytime I think the temp will hit 40 or below. I leave mine plugged in all the time because I am a Firefighter and you never know when you will get called out. I have even left it plugged in for over 24 hours before and have had no problems with do so. I don't notice if the electricity bill is any higher or not. I don't know what kind of amp draw comes from the heater. My recommendation is plug it in anytime you will need to run the heater.....it gets warm inside quicker.
Logistics Pro
Joined: Jun 2005
Posts: 4,243
Likes: 16
From: AZ
Originally Posted by mudmaker
I have to get use to plugging mine in again. The last 3 winters it slept in the heated garage. Now my wife insist her taurus and "our" X get the garage. I just plug it in all night when below 20. I havent noticed much in the way of electricity bill difference.
Logistics Pro
Joined: Jun 2005
Posts: 4,243
Likes: 16
From: AZ
Originally Posted by clux
A 7.3 engine in good condition with a properly operating glow plug system and good batteries will readily start at -20*F without being plugged in. I don't even consider plugging mine in unless the forecast is for lower than -10*F.
