The other day I installed a 1000W Kats circulating tank block heater in my Mirage. In my opinion this heater is amazing. I previously had it installed in my 1999 Chevy Metro and absolutely loved it. Turning it on for about a half hour, it would get the coolant temp over 100F. From there, you get heat just a minute or two down the road. A bit more time can get you heat nearly instantly. In my case, I kind of dial in the amount of pre-heat to avoid engine fast idle so I don't take as big of a fuel economy hit for 'cold' starts.
So, lets get to it, right?
Here is the block heater.
It must be mounted low compared to the engine. It works via natural convection. There is no pump. So, there must be vertical distance above it for the hot coolant to move, otherwise it will burn itself out. I ended up selecting a less than ideal location, but I think it will work. The heater is very low compared to the engine, but the hose runs are farther than I would like. The shorter the better ideally.
I mounted it on the driver's side of the radiator in front of the transmission. There is a mounting nut just sitting there that you can use an M6 (10mm head) bolt to mount it.
From there, I decided I wanted to tap into the lower heater core hose. The ends on the block heater are 5/8" and so are the heater core lines, so it makes it pretty easy. I got a 6 foot length of hose from the local autoparts store. It was about $6. I cut the lines to length with a little extra slack to allow for the engine movement. The outlet of the block heater went to the engine block. The inlet of the block heater went to the lower heater core on the firewall. The hoses don't have to be run this way, but that is how I chose to run them.
Note: If you use the included screw clamps you need to check their tightness in a week or two, and then again in another week or two. I didn't do this when it was installed on my Metro and I saw evidence of coolant leaking around the block heater and the block heater had crusty coolant partly blocking the outlet. I assume this has to do with thermal cycling and heat expansion, but it will work itself loose. The clamp on mine was barely tight at all when I went to take it off. This time around, I used spring clamps that I had pulled off other engines so I don't have that issue.
Now, the next part was a bit of a pain. You have to refill the coolant system and bleed any air out of it. When you are refilling the system, make sure you use Mitsubishi blue coolant, or a suitable aftermarket coolant like the one shown below.
In my case, some air got trapped in the block heater lines and was stubborn and wouldn't come out. I had to manually 'pump' it out by squeezing the 5/8" radiator hose lines coming out of the block heater. This pushed the air out and finally got the coolant flowing through the block heater. I could tell that there was air trapped because those lines were not hot while other ones were. I also wasn't getting any heat out of my HVAC / heater when I turned it on.
This morning was the first time I was able to use the block heater. As expected, it is awesome. It was 22°F / -5.5°C outside. I only had it plugged in for 20 minutes, but my coolant temperature when I started up was 83F / 28C. By the time I was out of my driveway, the coolant temperature was 90F / 32C. If we do some quick calculations, we can estimate that this heater warms the engine up roughly 3F / 1.7C per minute. If I plug it in for a half hour, I'm going to be leaving the with over 100F / 38C on all but the coldest days of the year.
I really like and prefer this kind of setup vs the 400W block heater. I have used both and do still use both. My Prius has a 400W 'slide into the block' heater. Their installation is super easy, and there is no draining and refilling the coolant. However, they are way less efficient simply because of their lower power output. In order to get the coolant temperature up to 83-90F, they would have to run for at least 3 hours. Three hours would make for 1200 watt hours or 1.2 kWh of power usage. With the 1000W circulating tank block heater, I run it for a half hour. So, I use 500 watt hours or .5 kWh for the same result. The reason being that it is SO much more efficient is it doesn't have those extra 2.5 hours to sit there and dissipate heat through that nice aluminum engine block. I can also use this heater on very short notice for unplanned trips vs waiting 3 hours for the other heater to warm the engine.
Another optional step is to add an AC port plug. Eggman turned me on to this specific one, but I've used a similar one in the past. This makes pluging in very easy, and gets rid of that plug hanging out of your bumper or hood. A nice improvement that I plan to add. I will update the thread when I get mine and install it.
I did this on my 2003 Matrix, and it turned out really nice.
What I really like to do is pair my block heater with a wireless remote switch like this. When I come home at night, I plug the car in. Power to the block heater is turned off. In the morning I wake up and do my thing. About 30 minutes before I know I am going to leave, I hit the remote button to start the block heater. When I go out to the car, I unplug it, hang up my cord and drive away with a nice preheated engine. This eliminates the quick run out to the car to plug things in before leaving, and its cheap too.