Anyone have instructions on how to replace the block heater on an LB7. Mine is out and I want to replace it before the cold gets here. Thanks in advance for assistance.

1st verify its not your cord. They are know for shorting out.

If it is the block heater, its a bit messy because you can't really get all the coolant out of the block. Drain as much coolant as possible! The block heater is located passenger side behind the a-arm in the wheel well. It removes with a screw driver. Its about a 30 min job, then you have to refill and bleed your cooling system.;)

I tested the cord. There is voltage all the to the connector for the block heater. I heard that you have to remove the motor mount or something like that to gain access. Not true??

No that's not true. All I did was remove the plastic inner fender. Half hour job like was said above.

Thanks. I will got one soon and change it out.

Just pull the wheel and fender liner on the passenger side. Drain all of your coolant (the drain on the radiator is easier to get to with the fender well out, anyway). Right beside the engine mount, you will see the block heater. Unscrew the screw in the middle until the resistance on the screw changes a bit. After that, it should pry out with little effort, and you can pur the new one in. Try not to scrape it on the block as you put it in. It needs to have the same orientation as the one you take out (I believe it points down). Tighten the screw (not too tight). Make sure that loosen the bolt on the thermostat housing while filling with coolant. Put it in when the air bubbles stop. You can figure it out from there.

Oh yeah, you do NOT have to remove the engine mount. Also, buy a dealership part. That one will be 1000 watt. Most aftermarket models, while cheaper, are only 400. That would be less likely to warm your engine enough in the cold, and would take longer to do it if it could.

So it is possible to buy just a cord? Mine trips the house breaker instantly (dead short).

So it is possible to buy just a cord? Mine trips the house breaker instantly (dead short).
What size breaker? 1000 Watts @ 115V = ~10 amps, so a 10A breaker might trip with everything working normally, especially if other devices are on the same breaker.

If the cord is shorted, that could cause the problem too. Try removing the cord, and checking for a short in it.

THanks Dave, I'm an industrial electrician ;)

It was a 20 amp breaker.....

guess I'll see if I can get the cord unplugged and put the continuity tester on it.....

I have gone to three shops in town here and they all say the 4.5 hrs and they all say the motor mount needs to come out so how did this work out for you Im driving a 2001 and it really looks to me like the motor mount is in the way.

where would you find the cord for the block heater? and does every diesel truck have one. i got a 2002 gmc sierra 2500 hd 6.6 trubo diesel 4x4.

where would you find the cord for the block heater? and does every diesel truck have one. i got a 2002 gmc sierra 2500 hd 6.6 trubo diesel 4x4.

Its kinda hidden. Look on the passenger side. It'll be tied up to a hose or pack of wire's but its there coiled up. :D

THanks Dave, I'm an industrial electrician ;)

It was a 20 amp breaker.....

guess I'll see if I can get the cord unplugged and put the continuity tester on it.....


Last year I found out that my cord was rubbed through and the only replacement I could find was at O'Reilies. After I went down and bought the new cord I noticed it was super cheap and had almost no insulation at all. And it was too short.... :mad:

So I took an old HD extension cord and wired it in. I just clipped the wires close to the plug that attaches to the heater and wired and sealed my connections. I also added an extra few inches so I could reroute it in a safer way.

where would you find the cord for the block heater? and does every diesel truck have one. i got a 2002 gmc sierra 2500 hd 6.6 trubo diesel 4x4.

Passenger side of the truck zip tied to the frame rail. You can look down from the top of the motor or you can peel back your inner fender well and find it that way.

I starred at it for about 20 mins before I found it :D

See my 02 Dually doesn't have one.. My 02 2500 Does and So does the 02 3500.

And its strange they are all Canadian vehicles

where would you find the cord for the block heater? and does every diesel truck have one. i got a 2002 gmc sierra 2500 hd 6.6 trubo diesel 4x4.

I replaced my coolant heater cord in Jan 2006, and installed GM #15118792, which cost $35. This was the non-thermostatically controlled cord, which was heat insulated near block and included the mounting strap.
Since then, GM may have changed ALL cords to the thermostat cords, because they wouldn't fix the P0181 code issue, (coolant temp and fuel temp difference > 18 deg F. when cold outside and heater is used).

what is a blocker heater used for? (i have a 2002 gmc sierra 2500 hd 6.6 trubo diesel that i just got.)

i went to a truck shop for OTR trucks and got my cord and a plug in mount that i installed in my front bumper so i don't have to pull the cord out every winter.

what is a blocker heater used for? (i have a 2002 gmc sierra 2500 hd 6.6 trubo diesel that i just got.)

http://en.wikipedia.org/wiki/Block_heater

I was told not to warm truck up when it is plugged in I burnt out my block heater when I lived up north. It only took about 45 minutes to change. with a bit of a mess on the shop floor.....

I changed my block heater this last weekend. Took a bit more than 45 minutes and the I made a pretty big mess. But it works and the motor mount does not need to be removed as I originally thought. If I ever have to do another one it will go much faster and smoother. Someone said it needs to point down but the orientation of mine was facing up so that is the way I put it back in.