good/best engine block heater?

[JethroBodine]

Saranac Lake, NY is, as often as not, the coldest town in the continental U.S. and sometimes including Alaska( they do keep track of this on the morning news that I watch). The record is from Northern Maine, -55F. We do get a little chilly here in New England.

Another vote for coolant heater first, oil pan heater second. I remember reading about the dipstick type heaters not being recommended when they first came out, but not sure what the exact reasoning was.

[California98Civic]

Originally Posted by JethroBodine

I remember reading about the dipstick type heaters not being recommended when they first came out, but not sure what the exact reasoning was.

I think the problem is in how the heat is distributed and damaging the oil.

[Piwoslaw]

Originally Posted by tinduck

Maybe you are right, but in THEORY the warm-air-blower-through-the-lower-grill has some advantages over oil pan or cooling water heaters:

- behind the grill is the water cooler => gets heated. Heat transfer should be great, after all this is an air-water heat exchanger.

The problem with blowing into the engine bay through the grill is just that: Most of the heat will be absorbed by the radiator, but the coolant in it won't warm the engine itself since the thermostat will be closed. Most of that heat in the radiator will be lost to the ambient air the minute you start driving. Of course, if the warm air is blowing all night, then once the radiator warms up the engine will start getting some heat. On the other hand, if the warm air is blowing all night, then it's not really warming a cold engine, but slowing the cooling of a hot engine after parking in the evening.

Still, any heat that gets into, and stays in, the engine is good.

Originally Posted by JethroBodine

I remember reading about the dipstick type heaters not being recommended when they first came out, but not sure what the exact reasoning was.

It's about the heat density, ie how much heat is emited per unit of surface area. I don't remember what the maximum limit is, but above that the oil starts to fry. A dipstick has very little surface area, so it would have to be very low power to be safe, but then it wouldn't do much.

[Hauki]

I have a 25 year old Volvo with the block heater in and it goes on as soon as the temperature drops around 0°C. I even used it tonight in 4°C (just to test it was still working before winter hits really..)

There are no real laws about when to turn your block heater on, I do it when temp gets around 0, some do it in -10, some colder. It is down to you. Most people do it to look after their engines and so the heaters work quickly. I don't think it occurs to them how much fuel it saves. I do it for all the above.

Block heater is much better than oil heater, because a block heater heats both oil and water, whereas a oil heater can heat only oil. Not many people realise this. Of course it doesn't directly heat the oil, but indirectly by thermal conduction.

It does this by heating the water which then travels through all the capiliaries in the engine, all the while the water is transferring this heat to the metal block itself, all over the engine. When the engine is started the oil then flows through the block, which is hot, and the heat is then transferred to the oil by conduction. The oil is very quickly warmed up due to flowing through hot block.

As for using air heaters in front of, or underneath car, it might make 1 degree difference. My air con/inverter on the side of the house iced up last winter, I had to get out there with a 2kw hair dryer to try and heat the thing to melt the ice, it was futile. I had to hold the hairdryer almost touching the ice to make it melt, it took a loooong time. You are just wasting time heating air infront of the thing rather than heating the thing itself. You would probably benefit more from lining your bonnet/hood with foil to act as a radiant barrier to keep engine heat in the bay.

[bhazard]

1000w Kats heater in my 2.2L impreza. Gets warm enough to keep a good portion of the windshield defrosted. I need to find a non-scoop hood for the car though, preferably with insulation. The scoop is blocked off at the factory but one of the previous owners removed said block thinking it would be an instant +25hp. Heater is fed by the lower rad hose and feeds into the heater core inlet.

[pletby]

Horror of horrors I plugged in my car this evening and I heard sizzling and snapping from under the hood. Sounds like my block heater cord is messed up. The cold hit today for the first time this winter and it's dark for most of the day so I'll be working on this tomorrow. Hope it starts at six in the morning. Gotta get ready for a Winnipeg winter!

[Diesel_Dave]

Originally Posted by pletby

Horror of horrors I plugged in my car this evening and I heard sizzling and snapping from under the hood. Sounds like my block heater cord is messed up. The cold hit today for the first time this winter and it's dark for most of the day so I'll be working on this tomorrow. Hope it starts at six in the morning. Gotta get ready for a Winnipeg winter!

Oh, the humanity! That's not good!

[slowmover]

As a CTD reference:

Came across a post by a retired engineer in Edmonton, AB runs a diesel-powered Dodge 24/7/365 in the oilfield:

. . I keep it plugged in when at home - start up temp 104 F
or 140F when on the road with the Espar heater running

EDIT:

And later today came across this (a little farther removed from topic):

http://en.wikipedia.org/wiki/Weather_Eye

AMC Weather Eye

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