Block Heater + Coolant Pump

[Blue Angel]

Originally Posted by Daox

What are the benefits of mechanically circulating the coolant?

In the traditional thermosyphoning system the flow of coolant is extremely slow. Because of this, a lot of heat is lost before the coolant even makes it through the lines and into the engine. Once in the engine the coolant loses its heat in the inlet side of the engine and is cold again by the time it comes out the other end, leading to an engine that's (relatively) hot-to-cold from one side to the other.

Because the rate of colant flow is so minimal, the high heat element typically boils the coolant inside the heater, leading to deposits forming on the element and eventual element failure. Also, the temperature of the coolant leaving the heater is so high that hose failure is common where it attaches to the heater.

A pump circulated system runs at much lower peak coolant temperatures, heats the entire engine much more consistently, and typically requires less power as well as heating in less time all due to less thermal losses at the heater outlet. The drawbacks are added system cost and complexity.

The industrial pump circulated heaters feature an optional thermostat on the coolant intake on the pump that cycles the heater to keep the engine at a pre-set temperature, another energy saving feature. This is a feature I would like to incorporate as well, but I need to jump the pump hurdle first.

The dishwasher drain pump I have will definintely pump water, but I have my doubts as to whether it will reliably survive the underhood environment as well as not become a source of a leak operating in a cooling system with a 20 psi rad cap.

High coolant temps shouldn't be an issue as the Zerostart heater has a one-way check valve integrated into the inlet to keep coolant from flowing back through it while the engine is running. As such, the highest coolant temps it should see will be the return temp while the heater is functioning.

[Blue Angel]

Found a couple that don't look too bad price-wise, but they're 12V. I would have to add a converter to the budget to power these from the wall. These are by far the cheapest I've found so far. Maybe a tour through the scrap yard is in order.

No name replacement:
PartsTrain.com - Hard to Find Auto Parts and Truck Parts -

Bosch:
PartsTrain.com - Hard to Find Auto Parts and Truck Parts -

[MetroMPG]

Originally Posted by TexasCotton

FYI
The dipstick oil warmer from Oreilly is junk

No surprise there - I bet it's a pretty low power output. I've seen them as low as 60 watts. Not good enough.

With block/coolant heaters, go big or go home.

[MetroMPG]

Originally Posted by Blue Angel

Those Katz heaters are effectively the same as the Zerostart I bought... there's no internal pump, the seller is mistaken and the circulation is from the heated coolant rising only.

Aha. Thanks for clarifying.

[euromodder]

Originally Posted by Daox

What are the benefits of mechanically circulating the coolant?

It doesn't necessarily start circulating all by itself when you start pumping in the heat.

We have free circulating heat exchangers @ work, on a slightly different scale though
Once it's circulating it's OK and it'll keep going, but getting it to start circulating is the hardest part.

[Blue Angel]

Originally Posted by MetroMPG

With block/coolant heaters, go big or go home.

Hence my desire to make an improved version! I figure if it works for megabuck backup generators it must be worthwhile for my little 1.4L turbo!

[Blue Angel]

Originally Posted by euromodder

It doesn't necessarily start circulating all by itself when you start pumping in the heat.

We have free circulating heat exchangers @ work, on a slightly different scale though
Once it's circulating it's OK and it'll keep going, but getting it to start circulating is the hardest part.

Excellent point, and at extreme cold temperatures the viscosity of the coolant mix will resist flow even more.

[oil pan 4]

You don't need forced circulation for 1000w.
Waste of time + money.

If you had something like this you would want forced circulation:
http://ecomodder.com/forum/showthrea...ghlight=heater

If you still want a pump don't use a dish washer pump, that sounds like a bad idea on so many levels. Get something that can handle engine bay heat, hot coolant and cooling system pressure for years.
Some Audis, VWs and BMWs have auxiliary coolant pumps that circulate coolant through the turbo after the engine is shut off.

http://newbeetle.org/forums/1-8-lite...flow-rate.html

[Piwoslaw]

I second using a heating pad on the oil pan in tandem with a coolant heater.

I assume that the engine is already insulated? Going to waste a lot of watts warming the outdoor air without insulation.

[Blue Angel]

From Hotstart's 'Tube channel.

Here's a good look at installation of a tank type circulation heater. It's done on an industrial engine, but the principles are the same:

http://www.youtube.com/watch?v=RxukiZsUUbM

Here's a video describing the differences between the thermosyphon systems and the forced circulation systems:

http://www.youtube.com/watch?v=wf3Tr...w4gqezxtgfmpZt

And here's a time lapse infra-red video showing the difference in how the two systems heat an engine (thermosyphon on the left and forced circulation on the right). Notice how evenly the forced system heats up:

http://www.youtube.com/watch?v=sfbqh...w4gqezxtgfmpZt