block heater on 03 5.3

Discussion in 'GM Electrical Tech' started by 03 SIERRA, Jan 21, 2013.

  1. 03 SIERRA

    03 SIERRA Rockstar 100 Posts

    Since I need a new water pump as well as a engine block core plug, that just happens to be the one for the oem location of the block heater im thinking of installing one. I've been doing some research and I've come to understand that the 99-04 iron block trucks are able to have a block heater non thermostat style installed and not throw a check engine code while being used when the ambient temperature is 1° to 32°. Now all the 05 and up aluminum block motors are not capable of this as I understand. I need an answer from someone who has experience with this. I do not want to go through this and have a useless block heater until it is 0° literally outside.
  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    I am now also interested in this! I don't understand why what year the truck is would matter. The block heater is used when the truck is off, so why would it throw a code? It does not connect to any of the electrical components of the truck. I am now hoping someone answers this soon

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    I did a little research, the cord that comes with the model for the 05 is has a thermostat in it and will only turn on at 0 degrees. You could easily fix that issue by purchasing a replacement non thermostatically controlled cord from a place like napa or buy an aftermarket heater that has a thermostat setting to turn on at 32
  3. 03 SIERRA

    03 SIERRA Rockstar 100 Posts

    the pcm recogonises that the ect is too warm in comparison to the ambient temperature sot it will throw code P0116. gm does this for somethig with the emissions so the motor is more efficient at cold start up on a 0* or below day. i was looking in other forums and people said that they cut the thermostat off the plug so they could use it any time they wanted but those were all 05 and up models with the aluminum block. they said it threw the code. im just wondering if anyone has ever put a heater in on a 99-03 motor? and what results they had?
  4. Skippy

    Skippy Member 2 Years 100 Posts

    Curious question. Why do you need a block heater? Typically, they're installed to keep oil flowing during extreme cold conditions (like below -10F to -20F). With 5w30 oil having a pour point of -42C (-43.6F), the block heater certainly isn't going to provide much value to you between the 1 and 32F (-17C and 0C) range. The oil may be thicker, but it most certainly will circulate through your engine just fine.

    Block heaters don't keep the engine block at an operating temperature, either, and with the massive power draw they pull (1200watts or more), they're certainly not economical, in terms of keeping your engine warm, vs. warming it up for 2 minutes before you get in.

    For my own education why would a person need a block heater for those "just cold" ranges?
  5. 03 SIERRA

    03 SIERRA Rockstar 100 Posts

    im not going out of my way to replace it. here in chicagoland it hasent been above 15* in a week. i would just like to start my truck in the morning and have it be half way warm. i may not need it im just seeing my options
  6. zigger215

    zigger215 Member 2 Years 500 Posts

    Block heaters are awesome if you live in cold places, cold!!! Place lol. Up here in Alaska we have them in Fairbanks on all our vehicles. If you don't have one and it gets -40, your truck is not going to start. But even 300 miles south of us in anchorage, they don't have block heaters in most vehicles. I wouldn't waste the time or money and I wouldn't wanna pay the electrical unless I had to. I only plug my truck in when I HAVE to.

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