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5.3L engine block heater

beasleyiv

By beasleyiv
in Ask A GM Technician

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ArcticJ Enthusiast

ArcticJ

Posted
Posted

If anyone has the means, I would greatly appreciate it as I now have two useless block heaters (05 burb and 06 71hoe) and its frickin cold out here :confused:

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MS3DALE Senior Enthusiast

MS3DALE

Posted
Posted

Didn't have a chance to call GM yesterday and won't be able to now until Monday.

 

Arctic you said in your earlier post something about how someone told you GM put the thermostat on there because they don't want the block heater maintaining a constant 180 F for fear of possibly damaging something internally? Did he say what?

I can't figure it out,It's baffling me :confused: ......I mean the engine runs a helluva lot hotter than that going down the road! Why would it hurt to keep the block warm when its 20 to 30 degrees F.

 

GM-Tech,Do you have any thoughts on that?

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted
GM-Tech,Do you have any thoughts on that?

 

I agree that the possibly damage theory doesn't make sense. Like you said, it runs hotter than that under normal conditions.

 

I'm sure there's some reason for it. Finding the guy that knows the answer might be difficult.

ArcticJ Enthusiast

ArcticJ

Posted
Posted
Didn't have a chance to call GM yesterday and won't be able to now until Monday.

 

Arctic you said in your earlier post something about how someone told you GM put the thermostat on there because they don't want the block heater maintaining a constant 180 F for fear of possibly damaging something internally? Did he say what?

I can't figure it out,It's baffling me :confused: ......I mean the engine runs a helluva lot hotter than that going down the road! Why would it hurt to keep the block warm when its 20 to 30 degrees F.

 

GM-Tech,Do you have any thoughts on that?

 

 

 

 

That was what I was told, and I asked the same question...in response, I got the same deer in the headlights look that the other service tech gave me when I mentioned that there is now a thermostat on the plug :cry:

 

I too agree that it makes no sense...the trick is to find what if anything has changed in the engine since 2002 because i had a working block heater in my 02 burb...no problems. OR, find someone who has either an 05 or 06 with the thermostat-less plug factory installed block heater...as the manual says, something along the lines of "some heaters may be equipped with a thermostat..."

If a 5.3 does not have the thermostat from the factory, its probably safe to assume that the engines are the same and therefore safe to lop off the thermostat and operate like it was supposed to be when its cold...not frigid.

 

OR check a parts manual and if when looking up the p/n for the block heater for either an 05 or 06 suburbanhoe, the manual does not designate the specific model with the thermostat, and there is no special footnote or other indication that the "old," usable model without the thermostat would otherwise damage the 05 or 06 engine, and/or indicates that the thermostat-less model is appropriate, then that too would be proof enough for me...off it comes

 

Just some more thoughts...I have no idea

Trouttrooper Enthusiast

Trouttrooper

Posted
Posted

I too went to the dealership a couple days ago asking why they put the weird plug on to keep it from working until below 0. There were 3 mechanics that happened to be behind the counter and all of them looked at me like I was stupid, none of them knew what I was talking about.

 

One guy finally said it was because "something" could burn up if it got too hot, but he couldn't tell me what or why "0" was such a magic number.

 

The other response as I was walking out the door was my truck would start above 0 and didn't need the block heater. :confused:

ArcticJ Enthusiast

ArcticJ

Posted
Posted

Hey...thanks for the information...someone out there in this forum knows or has the means to find out why this is...we will eventually find out (just not from my dealers or apparently in the northern rockies either)

 

:confused:

beasleyiv Enthusiast

beasleyiv

Posted
  • Author
Posted

Ok, I just couldn't wait any more. I bought one. The one I got doesn't have any bulge on the plug end. Looks like a standard three prong plug. I won't know if there is a stat until I get it installed, but I can hope.

dewfpo Senior Enthusiast

dewfpo

Posted
Posted (edited)
Ok, I just couldn't wait any more.  I bought one.  The one I got doesn't have any bulge on the plug end.  Looks like a standard three prong plug.  I won't know if there is a stat until I get it installed, but I can hope.

 

<{POST_SNAPBACK}>

 

 

 

 

Is there a P/N on the cord without the thermostat. It 3F right now and it's pissing me of that the block heater won't come on.

 

DEWFPO

Edited by dewfpo
beasleyiv Enthusiast

beasleyiv

Posted
  • Author
Posted

I don't see a part number, but here is the end of the cord for reference.

 

plug1.jpg

 

plug2.jpg

 

plug3.jpg

 

I don't see the buldge that everyone is talking about.

MS3DALE Senior Enthusiast

MS3DALE

Posted
Posted

Allright guys heres the latest I came up with,This maybe a little confusing and long so bare with me :D

 

I checked the service manual and heres the first thing it says about the heater not working:

 

"Important,The power cord will read open if the ambient temperature is above -1 degree F (-18 C)"

 

That would confirm what we thought all along,That it won't work above 0 F.

 

Then I called GM-Partech and explained to the agent what we are dealing with and ask him if he could confirm a "thermostat" in the plug or when it should and shouldn't work,Well he told me no thermostat exists and it should work as soon as you plug it in and continue working for as long as its plugged in. Great I thought,Now I'm more confused :cheers::wtf:

 

So I did some tests over the last few days here since its been in the single digits but above 0 degrees.

 

The first night (about 8 degrees F) I didn't plug my truck in and it had frost all up and down the windshield the next morning and when I started it up it took almost 15 minutes to get heat.

The next night (same temp.,about 8 F) I did plug my truck in and the next morning the windshield had no frost on the lower half and when I started the truck it only took a couple of minutes to get luke-warm heat and about five minutes to get almost full heat.

I know I said in an earlier post that it wasn't working before but to be honest I never really checked it that good, (Because I don't drive my truck everyday,heck it hasn't moved in a few weeks!)

What I was mainly basing it off of was the fact that in all my other trucks I could actually hear the heater working,Kinda like a slight "humm" is what I always heard on my other trucks when the heater was plugged in.

So now I'm really confused,I'm not hearing any kinda "humm" to verify it was working but I can't see how it wasn't working the night I had it plugged in since I had heat pretty quick and no frost on the lower part of the windshield.

 

The only other thing I think I'm going to do is unplug the cord from the heater and test it,If that can be done.

 

What do you guys think?

GM-Tech Senior Enthusiast

GM-Tech

Posted
Posted

I wouldn't rely on what one guy at Partech says anymore than I'd rely on what one of the guys at TAC says. I can talk to 3 different guys at TAC and get three different answers. It's really frustrating at times. Some of them are pretty sharp, others know little to nothing.

MS3DALE Senior Enthusiast

MS3DALE

Posted
Posted
I wouldn't rely on what one guy at Partech says anymore than I'd rely on what one of the guys at TAC says.    I can talk to 3 different guys at TAC and get three different answers.  It's really frustrating at times.  Some of them are pretty sharp, others know little to nothing.

 

 

 

 

 

Yep,I know exactly what you mean.

I might even call back just to see what another guy says.

Sometimes though I think I know more than they do,(No...sometimes I know I know more than they do :cheers: )

You probably feel the same way,I know our techs here do.

dewfpo Senior Enthusiast

dewfpo

Posted
Posted

It 17F degrees and I just plugged it in (thru a digital power meter) and it is reading 00 watts so it is not allowing power thru the cable at +17F. I have taken pictures of the plug for those who aren't familiar with it but don't know how to post them.

 

DEWFPO

ArcticJ Enthusiast

ArcticJ

Posted
Posted

A couple of things...Beasley is in the ? range with a 2003...that p/n may not necessitate the thermostat-plugged heater...like i said before...95, 99 and 02 did not have the thermostat, but the 05 and 06 do...i don't know when the thermostat began to be installed...

 

As far as the picture...different plug, both of mine are black with a circular "tumor" (a bit larger than a hearing aid battery) behind the plug.

 

Theres no question about the existence of the thermostat...if someone's heater is working intermittently, there is something wrong with that heater or the testing procedure...

 

As far as the Partech guy...first have him refer to the owners manual that states there is a thermostat which will not allow the heater to operate above 0 F and then ask him about it...perhaps he won't deny its existence

 

again, how can there not be someone at GM with the answer as to why this is...And from the posts, in addition to my own experiences, why when you as several people, who are supposed to be professionals in this business, do you get several different answers to the same question?

 

Just a thought from another forum...the combination of metal (block heater) and aluminum (block) causes corrosion when electicity is introduced via the heater...therefore, GM lowered the operable temperature thus greatly reducing the use of the heater and as a result, greatly reduced the potential problems from the corrosion issue...

 

sounds crazy, but its alot better than the stupid looks i get when i ask someone at the dealer about the thermostat :cheers::wtf::D

ArcticJ Enthusiast

ArcticJ

Posted
Posted

Another thought as I sit here lamenting the useless heaters in my trucks...

 

with GM cutting back on stuff to save money (wire gauges, engine comp light, glove box light...) perhaps they reduced the gauge of the wire for the heater however due to the significant draw, there was a problem with melting wires...instead of fixing this, they put the thermostat on to avoid the use above 0F, allowing the cold <0 temps to cool the wiring...

 

:cheers:

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