I ordered a GM block heater (what else? lol) for my 2002 Envoy, 4.2L I6. I live in the Detroit area, and I know what you are thinking - it doesnt get "that" cold here. But I do go up to northern Michigan in the winter alot and there have been times where its so cold in January-February (-30F or more) that the truck will barely crank over and doesnt build oil pressure for like 15 seconds, even though I use semi-syn 5w-30
So I found a block heater for around $30 and tackled it tonite. Heres what you will need:
1- 14mm allen socket (Autozone sells for $9.99)
1- very long 1/2" extension (16" or so)
1- 1/2" swivel socket
1- 1/2" breaker bar or ratchet (I used breaker bar)
The plug is on the drivers side of the engine that has to be removed. Its not your typical "freeze plug" its threaded into the block and takes a 14mm allen socket to remove. Its a PITA royally. You have to have arms like an ethiopian to get up through the frame and move around. But once you get the drivers side wheel off and see what you've got to work with, you will figure it out. There is a rubber flap towards the firewall side of the wheelwell - this is the best access spot, IMO. In front of the strut- towards the radiator- you can get your 1/2" extension through. You have to put the 14mm socket into the plug first. You'll see what I mean/
I believe its loc-tited from the factory because a very significant amount of force had to be used - I actually had to get a 2' piece of steel pipe over the breaker bar handle and sweat my nuts off to get it to budge.
After that, I let about 1 gallon of dex-crap drain out and contorted my body to get the block heater itself into the block. BE CAREFUL as to not crossthread!! You will be in a world of ca-ca if you cross thread this job. The new block heater comes with some sealant of some type on the threads from GM. It advises not to use anything on the threads and not to over-tighten.
After you get the actual block heater threaded into the block, you can install the wiring harness, which- Thank You Mr. Goodwrench- was the easiest part. It comes pre-clipped so that it clips right onto the main engine harness coming up towards the battery. Then it clips on with 2 acorn screws onto the back of your battery cover, and the cord itself is tucked within this little plastic "box".
All in all, it took about 1.5 hours from beginning to end. I look forward to using it this winter!
It seems like a very nicely made (not cheap) part. I recommend this to anybody who lives in the north or midwest, or any part of the Country where it gets really cold.
FYI, I bought it here:
The shipping was pretty quick and I believe I paid about $30. I also bought a GM battery warmer
I know, I went a little buck-wild with the accessories but what the heck, who doesnt love to add kewl stuff to their 'Voy!