Coolant heater - where to install?
 

I've found a universal engine preheater which can be mounted on the coolant line, so I had a look to confirm that I have enough room to fit it. The only place I found with tolerable dimensions would be on the coolant line from the bottom of the radiator to the water pump. This localization has three potential downsides:

1. It is out in the open, so most of the heat will be warming the air around the engine instead of the block itself.
2. It is on a flat strech of plumbing. I would think that the heating element should be on a stretch of plumbing which is inclined towards the engine, so the the natural circulation will carry heat to the engine block. I wouldn't want the heat to be circulating toward the radiator.
3. Even if the heat does rise toward the engine, then the first thing it will hit before entering the block is the water pump. Will this hinder the circulation?

Maybe these are all negligible and it's still worth mounting the heater? The car will go to the mechanic in a few days to replace the head gasket, so I need to order the heater by then.

Is there no way to install it on a heater core hose? That would be much more ideal. I've seen them rerouted across the engine bay, but at least you won't be heating up the radiator. :)

Agree with mounting near the heater core if possible. I'm memory serve me you want to avoid the radiator side do you the exhaust manifold and heat shield. It will wear our too quickly.

Would the heat circulate if the engine is off ? I was pondering your sump heater for my passat.

Yes it should, remember the radiator is blocked off by the thermostat, and I thought the heater core on the Civic was nearly as big as the radiator anyway. It should cycle like convection up the heater core through the water pump and engine back to the bottom of the heater core. However since we don't know the dimensions of the heater its hard to guess as to whether it will mount at the lower heater core connection.

When I left the car with my mechanic before the weekend we had a quick look, and the heater core hose has an internal diameter of only ~22mm, while the inline coolant heaters I've found are for hoses with 28mm or more:(

I did find that DEFA makes a heater for the PSA 1.1 engine (part #411766), which looks like this:
http://images.sklepy24.pl/48884976/4...efa-411766.jpg
but it is 3-4 times more expensive than the heater I found.

Maybe, I'll send an email asking if they could modify the heater casing for my needs. If not, then Theodor won't have get an engine heater:(

I\'m glad you asked this question. I never had thought about the significance of location for a coolant heater! I\'m lucky that you asked and many smart people have responded. I would have made a big mistake later this year when it started to get cold around here!

The ideal setup will be to place preheater on the heater core hosing with a pump for a coolant circulation. Don\'t know what\'s the material that was used to build that heater you\'ve mentioned but you can always find the way to downsize the outlets to fit the hosing of a heater core.

It looks like I\'ve found a heater that will fit the heater core plumbing. The only place it will fit is on the hose going from the thermostat up to the cabin, then up again and suddenly straight down to the water pump. When the heating element is plugged in, the heat will rise through the heater core, then to the pump, and only then into the engine block. Will there be any heat left by then?

The heater has it\'s own t-stat which disconnects it from electricity once it warms to 80*C, so when plugged in it will not be as hot as the hoses during normal engine operation. The maker of the of the heater even states that it can be insulated with with the same foam used on central heating plumbing. Of course this would have to stand temps as high as 120*C, but it would increase the efficiency of the heater.

Verry interesting treath.

I aim planning on installing water coolant glow plugs to heat up the coolant. But those will only be powered directly from the alternator after the engine is fired up. Was thinking of placing this inline in the cabin heater line. But is this the best place to heat up the engine as fast as possible?