5.3L engine block heater

beasleyiv · December 6, 2005

I have found 12497459 as the possible part number for an engine block heater. The description is:

5.3 liter MFI 8 cyl engine, 6.0 liter MFI, HO, V8, iron engine (6.0N), 4.8 liter MFI 8 cyl engine, 8.1 liter MFI 8 cyl engine (496 CID), 5.3 liter flexible fuel (gas/alc) 8 cyl engine with MFI.

Notes: t/w gasket 12560438 for vehicles w/LQ4 or LQ9)

Can you verify this would work on my 2003 5.3L 1500 4x4?

Will I need the gasket?

Thanks!!

ArcticJ · December 7, 2005

I have found 12497459 as the possible part number for an engine block heater. The description is:

5.3 liter MFI 8 cyl engine, 6.0 liter MFI, HO, V8, iron engine (6.0N), 4.8 liter MFI 8 cyl engine, 8.1 liter MFI 8 cyl engine (496 CID), 5.3 liter flexible fuel (gas/alc) 8 cyl engine with MFI.

Notes: t/w gasket 12560438 for vehicles w/LQ4 or LQ9)

Can you verify this would work on my 2003 5.3L 1500 4x4?

Will I need the gasket?

Thanks!!

<{POST_SNAPBACK}>

whatever the #, just make sure it doesn't have the thermostat in the plug otherwise it will render the heater useless above 0F, which is about 20 degrees too cold for me...

MS3DALE · December 7, 2005

It will work for you,However part number 12497459 has been changed to a new part number,17800530.

Either one will work.

(You won't need the gasket,The reason you need it for the 6.0's is because you must remove the engine oil cooler line from the block which the 4.8/5.3's don't have)

MS3DALE · December 7, 2005

One other note that I forgot to mention that the instructions don't tell you,If your truck is a 4x4,To make it easier to install the heater remove the front driveshaft from the front yoke,You don't need to completly remove it,just the front half from the yoke.(It takes an 11mm wrench to remove the bolts)When you do just push the driveshaft back towards the transfer case and lower it outta' the way,You might already know this but just in case,Be sure not to turn the driveshaft once removed from the yoke.(You want to install it back the same way for balance reasons)

If you have any other questions let me,I've installed a few of these over the years and have it down to about a 1/2 hour-45 min. job!

beasleyiv · December 7, 2005

Thanks for the insight. Which plug do you take out? The rear most? Does anything else have to come off to reach up in there?

MS3DALE · December 7, 2005

The one you remove is on the drivers side rear,above the oil filter,Its a brass 17mm hex-plug. (So you'll need a 17mm hex socket,plus a 24mm regular socket to install the heater)

Nope,You do not need to remove anything else.They don't even tell you to remove the driveshaft in the instructions,but man does it make it easier to install!

Let me know how it goes

beasleyiv · December 7, 2005

Oh, so I'm not taking out a freeze plug? This is what's going in:

That looks to be the standard freeze plug size. If this is just unscrewing a plug and putting this in that seems much easier than yanking out a freeze plug. My only other experience with doing a block heater was on a 1979 Toronado 350 diesel conversion motor.

MS3DALE · December 7, 2005

Nope,Its not a regular type freeze plug,It is threaded and actually screws in and out of the block.

The picture you have there is same one I have here at the dealership and is a "generic" picture so-to-speak.

Your heater will have threads on it.

beasleyiv · December 7, 2005

Sweet. Thanks for all the help. I'll be doing this in a couple of weeks.

beasleyiv · December 7, 2005

Hey, I thought of a couple more questions. First, how much coolant am I going to lose? Second, I've seen the recent posts about these heaters possibly having a thermostat that keeps them from working above 0 degrees C. Is this true?

MS3DALE · December 7, 2005

You'll lose about 3 gallons if you drain it from the radiator,If you just remove the plug and let it drain from there (Or shall I say "shower" you. Be prepared if you drain it this way,it goes everywhere!) You lose a little over 2 gallons.

I always use distilled water for mixing with the Dex-Cool.

I really never noticed the thermostat or "tumor" thats on the end of the plug that everyone has been talking about,I do know this though,I've plugged mine in many times when the temp. is above 0 degrees,but below 30,and it works.

MS3DALE · December 8, 2005

OK,Just to update you,I plugged my '04 in last night for the first time ever since I had it (It never really got cold-cold here last year so I never tried to used it) And lo-and-behold it DIDN'T work,It got down to the upper single digits/low teens but not below 0.

I know all my previous trucks (Which included a '94 S10 ZR2,'94 & '97 K1500 "OBS" trucks and a '99 K1500 "NBS" truck) worked no matter if it was below 0 degrees or not,so they must have put some kind of thermostat in the plug over the last couple of years

I know I'll be switching out the plug end like everyone else has done!

beasleyiv · December 8, 2005

Hmm, thanks for checking. Are guys just cutting off the end and wiring in a replacement plug? Is it possible for you or someone to call the techline and get a confirmation?

ArcticJ · December 9, 2005

Hmm, thanks for checking. Are guys just cutting off the end and wiring in a replacement plug? Is it possible for you or someone to call the techline and get a confirmation?

<{POST_SNAPBACK}>

Since I have been trying to get a definitive answer on this for some time now, I asked around with a couple of tech's in the chicago area about this thermostat controlled plug...one had no idea what I was talking about, one said it has always been that way (which it hasnt, my 95, 99 and 02 all worked regardless of temp) and finally the third guy said that he BELIEVES gm changed something internally in the engine and now does not want the block heater maintaining a constant 180 F when it is above 0 outside for fear of POSSIBLY damaging something internally...

Please, is there someone out there that can get a straight answer on this? I'm freezin here...

MS3DALE · December 9, 2005

Guys give me a day or two,When I get a free minute (Been out all morning plowing the lot here at the dealership!) I'm going to call GM-Partech on this and see if they can tell me something (I'm not holding my breath though!)

Arctic,Your right it wasn't always like this,As I said in an earlier post before all my other trucks worked no matter what the temp.