I have been doing some reading on engine block heaters. There is some info, but not a ton. So I hope some of this helps.

The heater is often installed on early Canadian models and some vehicles destined for Colorado, which may explain why some US models have them. Mainly 2005 models years. I read that at least one 2006 had one pre-installed from factory. The cord itself though its pretty much always missing unless at some point the heater package was installed by a dealer. The heater is not, by default, part of the cold weather package. So it seems that the heater was originally intended as an option that was brushed aside and some early vehicles had them installed on the line, less the cord.

OEM LR Part VUB504640 is for the heater package. But LR did not make the part, Temro did. Part #3100107 and you need cord part# 3600003. You can find this information here:
https://www.disco3.co.uk/gallery/thu...php?album=3801

In addition to above, I seem to have located some other options:

Zerostart 3100107 (same Temro number, different "brand")
https://www.oreillyauto.com/detail/b...100107/4871336

Ford part number 2W6Z-6D008-AA appears to be the same Temro heater. This part group includes a bracket and cord with mount points installed. Its intended for a Thunderbird I believe. (pic attached below)



Another option is a popular brand of engine block heaters, Kat's. 11463. Of all the options, this is the most available. I believe they are sold without a cord so you may need that bit also.


Seeing at all but the Kat's heaters are easy to find, I plan to order one and install it. And since there are absolutely no pics of the factory heater installed I will take plenty to help any others that wish to install one.

 

The adhesive pan heaters are definitely the way to go.

 

Which one do you use?

 

I got a 250 watt off Ebay a few years ago when I had my E300D Merc... can't recall brand name.

 

I have had an adhesive pan one on an old VW TDI, and wasn't a fan. It made very little difference here in the cold north. Other's experience may vary, perhaps mine was a cheap one. However, I have had circulating coolant heaters and frost plug style block heaters. Temro lists #3100107 for the LR3, installed in the left rear freeze plug.

This thread shows that some vehicles had a block heater fitted without a cord, and that a Ford cord could be bought and installed. The poster ended up buying one of the adhesive block heaters and had success.
Disco3 Thread

Calix also has a block heater option. Their whole system can incorporate a timer, battery charger and cab heater. Bit extreme, but if you're in a very cold area and motivated enough it could be nice...
Calix LR3
Calix System PDF

 

I have not heard a single good thing about oil pan heaters, hence the block heater. I did look into circulating in-line heaters from Kat. But its something "extra" in the system I would like to avoid for now. I did order the Kat 11463 heater. While I was going to replace a lot of the cooling stuff (hoses, t-stat housing, etc.) my plan now is to install the heater and flush the system with a re-fill of the less expensive Zerex Dex-Cool ($14/gallon concentrate at War-Mart). Since I dont know the age of the coolant in the system, this will get my by just fine til spring when I do the overhaul.

Of note on the Kay block heater, I have not received a shipping confirmation yet. So if its NLA for some reason, I may try the circulating type anyway. They are generally considered the most effective heater system to install form what I have read. And probably easier to install.

 

I went with the unit closest to an OEM solution and while it was likely the most expensive it was still reasonable and it's a very integrated approach.

 

The Kat's unit arrived today. Since Kat's specializes in this stuff, I will trust that the gasket provided will hold up fine. But I generally have a preference to soft metals or o-rings for sealing coolant stuff. But the gasket is thick and solid. The other "issue" is that the plug fits nice, but I feel there is a gap around it. Really thats probably the case with any of them, but I will put a little Reinzosil around the plug before installing to ensure a 100% water tight connection. On the unit itself I see they did apply something to the plug prong base to water seal it. Can see the reflection in the pic below.

Not sure when I will get to the actual install, probably after the holidays unless we get hammered with the storm they are chatting about. I plan to take pics and maybe some video so we finally have some decent documentation on the block heater.

 

So, how was the install ? Did you have to lover front diff or managed the install without fiddling with diff at all ?

 

Never did it yet, other projects came up this summer. So the heater is still sitting on the shelf. I wanted to make it part of a cooling system overhaul since I have to dump the coolant. So new crossover and water pump with a heater core purge. Given the temps into the end of December, it may not happen til next year now.