I tried searching, but wasn't able to find answers to my questions. I'm looking to purchase a block heater but heard that there are at least 5 varieties: one that heats your water, one that replaces your dipstick, one that bolts in to some port on the block, one that goes in the oil pan, and one that you magnetically stick to the outside of the oil pan.

1. Which varieties are available for the 4.0 XJ?
2. Which work best?
3. Some goon tried telling me that the oil heating variety can break down the oil due to extreme heat. That makes no sense unless they heat the oil to better than about 300 degrees F I'd imagine. Is the guy nuts or do some have the ability to heat the oil that much?
4. I found this heater posted on the forum (http://www.jeepsareus.com/Merchant2/..._Code=CHEROKEE) Which variety is this and does anyone have experience with it?

Sorry for the basic questions. This is my first time living in a consistently cold climate for any period of time.

EDIT: I did some preliminary research and I was only able to find the type that go into your "freeze plug" hole. This is the best priced one I could find (I don't know about shipping costs though). http://jeeppartspeople.com/searchpro...e+Block+Heater

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I'm still awaiting mine to show up, I ordered the one you linked above. Hoping it comes today so I can put my jeep back together. I will update my findings with it but I suspect it will do the job well. It replaces a freeze plug and is submerged in the anti-freeze. the heat travels quickly through fluid to the rest of the cooling system.

I just removed another type of heater from the truck that was spliced into the lower radiator hose. I ordered the new one before I found it like a bone head. I gave it to a friend with a 70's ford 4x4 that does not like to start in the cold.

 

When you get the work done, please let me let me know how it goes and detail the process. From what I hear you just drain some coolant, remove a frost plug by hitting it with a hammer and punch into the block then grab it with a large pair of channel lock pliars, lube the O-ring and install. BUT, I've never done it before and I'm not too excited about hitting my engine with a hammer. I'm such a wuss.

s

 

will do.

with my truck I am hoping it will be a nice way to fix a leaking freeze plug. I had to take the intake manifold off, but I think you may be able to access the front most block freeze plug without too much effort.