Here are some pictures of the Mopar block heater for the JK. The kit includes heater, shielded harness, wire ties, and instructions.
It says 400 watts on the brass body. That seems a little small, but people who have it say it works well.

 

has anyone installed one, how is it done, through a freeze plug?? pictures>>

 

It installs into the middle "freeze" plug hole on the right side of the engine.
I will be installing this in a few weeks. I don't get a day off the whole month of February.

 

Is it all plug and play or do you have to drain the engine first? Is there directions or a write up somewhere?

 

If you are fast enough there is no need to drain the engine, just have the block ready to go and close so when you get the freeze plug out, you can put the block heater in its place. I have done on other vehicles and it can get messy, it is faster than draining the antifreeze but I would not suggest trying to do it without a lift, so you could be standing; not laying in it. No lift=drain the antifreeze. Good luck

 

I'm assuming that this is the one that my JK came with from the factory.

I have my block heater on a timer that comes on at 5:00am and I leave between 7:00 and 7:30 typically, some days a bit later. The timer is programmed to shut off at 10:00am.

It was cold enough to use the block heater last week, it was roughly -25C on a couple of nights and my ScanGuageII reported a coolant temperature of 15C right after I cranked it over. Without the block heater it will report very close to ambient air temperature right after it starts.

 

I plugged mine in a couple weeks ago when it got really cold and noticed a difference. Didn't get heat right away, but it definitly started and ran better than without plugging it in.

 

I installed mine in September. You do install it in the one of the freeze plugs which is a pain in the ass to remove because you have limited space. It's not had to install really, it just takes time. I highly recommend draining the system, I did and when there was a whole bunch of metal shavings from the machining of the rad and or engine block. I reused my coolant as it was still new, I just used a filter to catch any impurities. Just use a new, clean bucket. Main difficulty is they coolant system needs to be flushed with pressure. I opened the rad cap and drain cock, the rad drained but coolant in the engine does not drain. A pressurized flush will get that out. I didn't and when I popped the freeze cap, about a gallon of coolant came out.
It works great as the heater will be full effect in less than 5 minutes depending on outside temperature. Mine is garage kept so that helps keeping the Jeep warmer. Put Super-Lube on the rubber seal before installing as per instructions. Super-Lube is not petroleum based so it will not eat the rubber seal. You can get the lube at any good hardware stores. They come in small tubes.
Good luck.

 

poppakristof,

Thanks for the pointers. Your info will come in handy.

 

i had mine plugged in a few times -15*C or more
one day it was -23*C and when i crancked it over on the scan gauge it was at+23*c that's a 40*C difference I was pretty impressed I was thinking it was more than a 400watt unit that is impressive.
Us canucks love our standard equip block heaters.