Another Block Heater Thread with a twist

[brucey]

Went and got a Kat's Circulating heater for the car instead of using an OEM style. Mainly because I've seen the 'in block' kind before and wasn't too impressed by it.

But they appear to be designed for american V8's and not bizarre subaru motors, there is a couple things of the boxer design that have me confused on where to place this thing:

Here and Here are the instructions that came with it.

Simple right?

Except I can't tap into the lower radiator hose because of the location of my thermostat, and I can't tap into the coolant drain plug on the block because I don't have one. I just have this giant one where the OEM style goes.



The thermostat is below the water pump, which would block the path for the lower radiator hose.

I can't really make sense of it. Right now my best idea is going to take the coolant drain out and drill and tap it for the 5/8th hose connection. But I'm having a hard time finding a tap that large. The one that came with my tap and die set doesen't have anything that large.



Any help from you guys would be appreciated, as I want to get this done before the weather gets cold and nights are already getting to 50F.

[RobertSmalls]

I figure you'd want it inline with your heater bypass hose. The lower radiator hose is on the wrong side of the thermostat.

Inline with the heater core would be okay, but you don't want to spend too much electricity heating the cabin, and you'd have a problem if you parked with your climate control set to "cold".

If your existing heater core bypass plumbing is inaccessible, you could always put a T on the heater core input and output lines, and install the heater between them, right?

[Phantom]

Can you just place it in line before the water pump so it is directed to both sides of the block.

[brucey]

Would installing them inline with the heater core hoses heat the entire block though? It's my understanding that wouldn't happen since the electric heater needs to be installed on the lowest point for the "In" line. It circulates via thermosyphon from what I can tell.

[bhazard]

You HAVE to have a sizable coolant supply for it. I fried two because I tee'd off the heater hose and there simply wasnt enough cool water going into the heater, and the element fried. Either figure out the lower rad hose or pull from the block drain, or make a block drain.

These things are serious a pain to set up but they are pretty rewarding.

[brucey]

Looking at the FSM a bit more today..

Would I be wrong to assume that the heater core hoses entering the water pump bypass the thermostat, judging from this picture?

If it does, this install just got a whole lot easier.

[vtec-e]

The heater core supply pipes are more than likely connected to the block directly. If you want to thermosiphon through there you will have to pay close attention to your pipe layout. I tried to get mine to thermosiphon but i had no joy there.
I made up a 1KW, convertable to 2 or 3KW...heh!, tank type heater and put a domestic circulation pump on it. Good flowrate thats for sure!
Then i teed off the cabin heater pipes to the heater. The radiator return pipe went through the thermostat on the engine block so connecting there was not going to work. This means that i have to make sure my cabin heater control is set to cold. It's not a biggie as it helps keep frost off my window if i open it a little.
But my heat up times are still long. I guess the alloy block is good at dumping heat. I have a layer of foiled insulation on top of the engine but it's getting shabby after a years driving. Still, a warm engine at stsrtup is hard to beat.

[brucey]

For future reference, I ended up installing it on the small (5/8th) return hose that bypasses the thermostat.

Here is a picture of where it is on the coolant system, and it's actual location if anyone else wants to do this. I think the pictures help paint a pretty clear picture, if anyone has any questions I'll be happy to answer.

[NeilBlanchard]

Isn't the block heater supposed to be mounted vertically?

[brucey]

Yes, but it appears to work fine this way. I can't fit it in my engine bay vertically, since the engine is flat, so must everything else be.