ultraclyde
ultraclyde PowerDork
10/23/17 4:28 p.m.

The old diesel us much easier to start below 50* if I run the plug in block heater. I have a HD timer set to come on about 3 am and turn off at 7am when I go to work. It's always been pretty stiff to unplug the extension cord from the plug on the truck, and This morning it seemed extra hard. When I came home tonight and tried to plug it in I realized that one of the spade terminals had pulled out of the plug on the truck and was still jammed in the extension cord.

 

Is it okay to replace the plug end on the truck wiring with a suitable outdoor plug from the hardware store?  I'm thinking about buying a short, heavy gauge cord, cutting the plug end off, and soldering it onto the truck wires.

Am i missing any red flags? Id hate to burn down the truck and the shop in one shot.

stuart in mn
stuart in mn UltimaDork
10/23/17 5:37 p.m.

You buy just the plug and replace that, it will be easier.

ultraclyde
ultraclyde PowerDork
10/23/17 5:50 p.m.
stuart in mn said:

You buy just the plug and replace that, it will be easier.

I'm guessing a guy in MN has plenty of experience with block heaters, so that sounds like good advice.

rslifkin
rslifkin SuperDork
10/23/17 6:34 p.m.

As long as whatever parts you use are sufficiently weatherproof, properly installed and rated to carry the power the block heater draws, it'll be fine.  Just remember the 80% rule.  Continuous power draw should be no more than 80% of the max for the wiring, plugs, breakers, etc.  So choose parts accordingly. 

ultraclyde
ultraclyde PowerDork
10/23/17 7:01 p.m.

I believe the heater is 1500watts, so I'll upsize appropriately from there.

Appleseed
Appleseed MegaDork
10/23/17 7:05 p.m.

Did exactly that with the 4Runner ' s plug that disintegrated in my hands. Works fine.

rslifkin
rslifkin SuperDork
10/23/17 7:19 p.m.
ultraclyde said:

I believe the heater is 1500watts, so I'll upsize appropriately from there.

In that case, 15 amp stuff is just good enough, 20 amp is better.  Of course, a true 20 amp plug won't fit a standard house outlet...

BrokenYugo
BrokenYugo MegaDork
10/23/17 10:57 p.m.

Follow the wire back to the heater, I think most are replaceable, if so just get a whole new one and spray some WD40 in your extension cord to loosen it up and not stress the new cord.

For water/corrosion resistance I'd feel better about a one pice plug/cord properly spliced in than a replacement plug.  With such a short run at 1500 watts #14 wire should be adequte, #12 would be great. 

ultraclyde
ultraclyde PowerDork
10/24/17 6:48 a.m.

Water resistance is the reason I was originally thinking about splicing in a couple feet of HD extension cord, definitely 12 gauge. Plus I could add a little length so the plug could be stowed out of sight instead of being zip tied to the brush guard, which is a plus.  I'm running a 25' extension cord through the timer, and both are rated for 1800 watts @110v but use standard plugs. 

rslifkin
rslifkin SuperDork
10/24/17 8:02 a.m.

Thinking about it, for weatherproofing, I'd be tempted to mount a waterproof shore power receptacle into the front bumper.  Then once you unplug and stow the cord there's no connections exposed to road salt, etc. while driving.  Something like this: 

APEowner
APEowner HalfDork
10/24/17 10:15 a.m.
rslifkin said:

Thinking about it, for weatherproofing, I'd be tempted to mount a waterproof shore power receptacle into the front bumper.  Then once you unplug and stow the cord there's no connections exposed to road salt, etc. while driving.  Something like this: 

I was planing on doing that to my Super Duty when the last block heater plug burst into flames right after I pluged it in.  Instead I move to New Mexico and just installed a standard replacement plug.

rslifkin
rslifkin SuperDork
10/24/17 10:29 a.m.

As an additional suggestion, the fixed plug would make it easier to also add other stuff to the system if desired, like a small battery charger to keep things topped off while it's plugged in and/or an additional small heater on the oil pan and maybe trans pan.  

ultraclyde
ultraclyde PowerDork
10/25/17 5:15 a.m.

Thanks for all the feedback.  For what it's worth, I found out I could get a full replacement cord off Amazon for about what I'd pay for a heavy duty extension cord at the local hardware store. It plugs into the heat element on one end and has the plug on the other so no splices to fail, and it was $15 on Prime. And I can plug in the new cord in less time than it would take me to properly solder in a splice.

 

I looked at a couple shore power type plugs. That may be a future upgrade. Honestly, I'm in central Georgia, so this is more about convenience than actually making sure the truck will start. It just starts easier.  It never gets worse than the high teens here, and that's rare. Plus no road salt. 

Streetwiseguy
Streetwiseguy UltimaDork
10/25/17 7:47 a.m.

The only time it's really important to use the factory style cord is when it is temp sensitive.  GM trucks, for the last decade or so, won't allow the block heater to operate above -20C.  The ecu compared intake air, ambient and coolant temp above that, and when it sees the temp difference caused by the block heater, it sets a code and defaults to a limp home temp.  The truck then won't start in the cold because it's too lean...  Clear the temp code and off you go.

Kinda irritating.

mad_machine
mad_machine MegaDork
10/25/17 9:05 a.m.

In reply to rslifkin :

1500 watts at 120v is about 12.5 amps. 15 amp plug has a little overhead.

 

Watts = Volts X amps

1500/120 = 12.5

 

What you might want is this Hubbel weatherproof male receptacle

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